The Role of Public Policy in the Enforcement of Foreign Custody Judgments: An Example of Joint Custody in Turkish Law

: Societies transfer their basic values to new generations through child custody within the family. Therefore, bringing up children in healthy families is beneﬁcial to society. Despite the importance of maintaining the sustainability of the family, which is the basic unit of society, when family sustainability is not possible, a basic duty of the courts must be to provide the best custody model for the welfare of the child after the dissolution of a marriage. Studies have shown that children have a better psychological state and can more easily overcome the trauma of divorce when the courts rule for joint custody than when the courts rule for sole custody. Joint custody, provided for in many legal systems, is not regulated in Turkish law. Thus, requests for the enforcement of foreign joint custody judgments are rejected by Turkish courts for violating public policy. Turkish courts incorrectly consider foreign law, which provides di ﬀ erent rules, as grounds for public policy intervention. In this study, it is found that Turkish courts can rule for joint custody by depending on international conventions. Within this framework, it is not possible to reject the enforcement of foreign joint custody judgments by depending on the public policy exception.


Introduction
States exercise their sovereignty through their legal branches. The legislative branch makes laws, the executive branch applies these laws, and the judiciary resolves conflicts within the framework of these laws to protect the public order. These branches act in the name of the state's sovereignty. For this reason, states do not allow other states' legal institutions to intervene or participate in the functioning of their country's legal branches [1][2][3]. Consequently, the judgments of courts have an effect only in the countries in which they are given [4][5][6] and cannot be enforced in other countries. It is not possible for the courts of a country to directly give instructions to the public officers of another country, i.e., the executive branch of a country does not function by depending on a judgment given in a foreign country [7,8].
When a judgment is obtained from a court, parties may wish the mentioned judgment to be recognized and/or enforced in a foreign country. The aim is to achieve transnational legal certainty and to avoid repeated litigation. This will also prevent expenses for re-litigation and would promote a stable and uniform international order [9]. Some perspectives suggest that with regard to the recognition of foreign judgments, a foreign forum may be considered more appropriate. Furthermore, recognizing foreign judgments may lead to "the implementation of a policy that does not make the plaintiff's choice of forum depend on the availability of local enforcement" [10] (p. 972). Although this is the case, we cannot expect the judgments of one state's courts to automatically have an effect in another state. This is contrary to states' sensitivity regarding their sovereignty [11]. Therefore, states use recognition and enforcement procedures to ensure that foreign judgments that will have the same force as their own judgments [10] are not the result of a deficient foreign procedure or that the outcome of the foreign judgment will not be objectionable [12]. In other words, if the requested court is convinced that a matter has been adequately decided by a foreign court and there is no need for further litigation, the foreign judgment can be recognized [10]. It should also be noted that states are not under an obligation to recognize or to enforce foreign judgments because of the principle of the equality of states [13].
It is possible to discuss two different effects of foreign judgments. With recognition, it is accepted that the foreign judgment presents a fact or has a conclusive effect [1,4,5,9,[14][15][16][17]. In other words, "recognition of a judgment means treating the claim which was adjudicated as having been determined once and for all" [11] (p. 115). Recognition can also be expressed as a foreign judgment becoming legally valid in the country where it is recognized [18]. On the other hand, with the decision of enforcement (exequatur), the successful plaintiff enforces his judgment in another country. Enforcement can also be defined as "...a procedure securing the enforceability of a foreign court judgment as if it is a judicial decision given by the courts of the country undertaking the enforcement action" [19] (p. 57). It should be noted that foreign judgments that require the defendant to give something (dare), to do something (facere), or not to do something (nonfacere) require a judgment of enforcement, while foreign judgments that show the existence or nonexistence of a right or a legal relationship only require recognition. It is also possible to say that foreign judgments on the creation of a new legal situation or a change of content to or termination of an existing legal situation require recognition [8].
In a globalized world, persons and assets can easily move from one country to another, which makes the law of the recognition and enforcement of judgments more important. With the growing importance of recognition and enforcement, the number of bilateral and multilateral treaties regarding recognition and enforcement has increased. With the increase in the number of child abductions and to protect the best interests of the child, efforts regarding the recognition and enforcement of foreign judgments on custody have also increased.
Nevertheless, it should be emphasized that conventional law and domestic laws provide different rules regarding recognition and enforcement. Exceptions to the recognition and enforcement of foreign judgments are narrowly interpreted in treaties, so a more liberal tendency can be observed. In contrast to treaties, states rely significantly on public policy exceptions when they believe that a foreign judgment is incompatible with domestic law [12].
Statistics indicate an increase of divorce rate in Turkey which will be 1.93 per thousand in 2023 [20] (p. 45) that is believed to be a social problem. Unfortunately children are the victims of the whole divorce process. Studies have shown that children have a better psychological state and can more easily overcome the trauma of divorce when the courts rule for joint custody than when the courts rule for sole custody. In the Turkish Civil Code (TCC) there is no provision regarding joint custody and this leads to discussions whether it is possible for Turkish Courts to rule for joint custody. On the other hand, as rules regarding custody are mandatory, the Turkish Court of Cassation rejected to rule for enforcement of foreign joint custody judgments by depending on public policy exception. If it serves for the best interests of the child, joint custody may not only beneficial to children and parents, but also decrease the number of international child abductions and human rights violations. The aim of this study is to show that to rule for joint custody under Turkish legal system is possible and foreign joint custody judgments can be recognized as long as the best interests of child are taken into consideration. It should be noted that oral and/or physical violence is a frequently observed ground for divorce in Turkey. In a research made by Aktas 69.3% of woman declared oral and/or physical violence as a ground for their divorce [21] (p. 55). That is why Turkish courts should pay great attention while deciding the model of custody. For this reason it is suggested that instead of amending the TCC in a way regulating either sole custody or joint custody as a principle and the other as an exception, right of discretion must be given to judge to choose the best for children.
In this study, how the public policy exception is regulated in international law with regard to custody judgments is analyzed. Within this framework, special attention is given to the concept of public policy in private international law. The conditions required for the enforcement of foreign judgments under Turkish law are also discussed. Because the main concern of this paper is to examine foreign joint custody judgments, this study examines the concepts of custody and joint custody, how custody is regulated under Turkish law, including international conventions on joint custody in cases of divorce and the principle of the best interests of the child. Finally, this paper discusses whether foreign joint custody judgments violate Turkish public policy and whether it is possible to enforce such judgments.
The research encompasses two research approaches including literature review, legal documents and court decisions analysis. Literature review includes previous research and academic studies and discussions on the scope of joint custody and public policy exception regarding enforcement of foreign custody judgments. The study focuses on the research subject from the private international law and civil law perspectives.

Public Policy Exception in International Conventions Regarding Custody
The European Convention on Recognition and Enforcement of Decisions concerning Custody of Children and on Restoration of Custody of Children was adopted in Luxemburg on 20 May 1980 [22]. The Convention was signed on 20 October 1997 and became enforceable in Turkey on 01 June 2000 [15]. As stated in the preamble, the aim of the Convention is to ensure that decisions regarding the custody of a child can be more widely recognized and enforced, and will serve the best interests of the child. Within this framework, the Convention concentrates on the protection of the right of custody, the establishment of personal relationships between the parents and the child, the return of children who have been improperly removed across international borders, and the restoration of custody. Because the Convention is only enforceable among the member countries of the European Council, its enforceability is limited. The field of application of the Convention is also limited by the adoption of the Convention on the Civil Aspects of International Child Abduction and the Convention on Jurisdiction, Applicable Law, Recognition, Enforcement and Co-Operation in Respect of Parental Responsibility and Measures for the Protection of Children.
The first question that needs to be answered with regard to the Convention is that of who can be considered a child. The Convention states that regardless of nationality, a child is any person under the age of 16 who does not have the right to independently determine his/her own place of residence according to his/her national law, the law of his/her habitual residence, or the internal law of the state addressed (Article 1).
According to the Convention, decisions regarding custody cover decisions given by judicial or administrative authorities about the personal care of a child, including the right to decide on the place of the child's residence or the right to have access to the child (Article 1). It should be noted that the Convention only covers personal issues regarding custody; rights and obligations regarding the property of the child are outside its scope.
If a decision regarding custody of a child has been given in one of the states party to the Convention, other contracting states are obligated to recognize or give a judgment of enforcement, if necessary (Article 7). With regard to enforcement, the decision must be enforceable in the country in which it was given.
The Convention aims to both serve the best interests of the child and to protect the holder of the right of custody depending on a court decision [23]. If the effects of the foreign court decision are manifestly incompatible with the fundamental principles of the law relating to the family and children in the state addressed, recognition and enforcement of the decision may be refused (Article 10). As indicated by the aforementioned provision of the Convention, this provision seems similar to the public policy provisions provided under other international instruments. However, instead of attempting to protect all of the value of public policy exception, the aim is only to limit the enforcement of a foreign judgment if it is contrary to basic values regarding child and family law.
Another international instrument that is not directly related to the recognition and enforcement of foreign custody judgments but should be discussed is the Convention on the Civil Aspects of International Child Abduction [24]. The Convention was concluded on 25 October 1980, and Turkey became party to it on 1 August 2000. In the preamble of the Convention, it is emphasized that the interests of children are of paramount importance in matters relating to their custody, and children should be protected from the harmful effects of their wrongful removal or retention. The Convention therefore aims to secure the prompt return of children who are wrongfully removed to or retained in any contracting state, and to ensure that rights of custody and access under the law of one such state are effectively respected in the other states party to the convention (Article 1).
The right of custody under the Convention involves rights related to the care of the person of the child and, in particular, the right to determine the child's place of residence (Article 5). In contrast, rights of access, which are also within the scope of the Convention, refer to the right to take a child for a limited period of time to a place other than the child's habitual residence (Article 5). Under the Convention, any person under the age of 16 is a child, and the Convention can be applied to any child who was consistently resident in a contracting state immediately before any breach of custody or access rights (Article 4).
The Convention regulates the grounds for refusal of the request for return of the child by stating that the return of the child may be refused if it would not be permitted by the fundamental principles of the requested state with regard to the protection of human rights and fundamental freedoms (Article 20). Although the mentioned provision does not directly state the public policy exception, the values that it attempts to protect are similar to those protected by the public policy exception.
The third convention that needs to be examined is the Convention on Jurisdiction, Applicable Law, Recognition, Enforcement and Co-Operation in Respect of Parental Responsibility and Measures for the Protection of Children [25], which was concluded on 19 October 1996 and became enforceable in Turkey on 01 February 2017. The Convention aims to improve the protection of children in international situations by confirming that the best interests of the child are the primary consideration under the Convention. One of the objects of the Convention is to provide recognition and enforcement of measures taken to protect the person or property of the child in all contracting states (Article 1). The mentioned measures include issues relating to the right of custody, such as the care of the person of the child and, in particular, the right to determine the child's place of residence, as well as rights of access, including the right to take a child for a limited period of time to a place other than the child's habitual residence (Article 3). The Convention considers a child to be any person under the age of 18 years (Article 2). It should also be noted that the Convention does not apply to contesting a parent-child relationship (Article 4).
Recognition and enforcement are regulated under Chapter IV of the Convention. According to Article 23 of the Convention, the measures taken by the authorities of a contracting state shall be recognized by the operation of law in all other contracting states unless such recognition is manifestly contrary to the public policy of the requested state when the best interests of the child are taken into account. As in the cases of previously studied conventions, public policy is again an exception to the enforcement of decisions given by foreign authorities. It is obvious that public policy is not only a generally accepted exception in domestic laws but is also a well-recognized principle in international law. This Convention replaced the 1961 Convention Concerning the Powers of Authorities and the Law Applicable in Respect of the Protection of Infants, which became enforceable in Turkey on 24 October 1983 after being published in the official gazette on 21 February 1983 [26]. For contracting states such as Turkey, which are party to both the 1961 and 1996 Conventions, the 1996 Convention is enforceable, while for states that are only party to the 1961 Convention, the former Convention continues to be enforceable [3].
The 1961 Convention aims to adopt common provisions regarding the powers of authorities related to the protection of children and the applicable law. The Convention regulates the recognition and enforcement of decisions given not only by judicial authorities but also by administrative authorities. The Convention provides automatic recognition of the measures taken by the competent authorities in contracting states. Unlike recognition, for enforcement of the mentioned measures, Article 7 requires the satisfaction of the conditions required by the domestic law of the country in which enforcement is sought or by the relevant international conventions. The Convention is applicable if the residence of the child is in one of the contracting states (Article 13). According to the Convention, an infant is "any person who has that status, in accordance with both the domestic law of the State of his nationality and that of his habitual residence" [26] (Article 12). Under Article 16 of the Convention, it is clarified that the application of the provisions of the Convention can only be refused if such application is manifestly contrary to public policy.

The Definition and Characteristics of Public Policy Regarding the Enforcement of Foreign Judgments under Turkish Law
Public policy is a vague and overly broad concept that must be discussed due to the lack of a finite list of cases for which public policy can be invoked [6,[27][28][29][30]. There are two dimensions of public policy in private international law. The first dimension is to prevent the application of foreign law, and the second dimension is related to the recognition and enforcement of foreign judgments [31,32]. When the enforcement of foreign judgments is considered, public policy is an exception that gives a court the authority to refuse to enforce a foreign judgment because the enforcement would violate the public policy of the court's country [33]. At this point, it should be emphasized that the concept of public policy must be narrower and more limited in private international law than in domestic law [28,29,34].
Depending on its nature, public policy changes in time and place, which makes it difficult to define [17,[28][29][30][31][32]35,36]. It is also impossible to list all cases that can be considered under public policy [37]. While defining the concept is indeed difficult, some definitions have been proposed [38]. The Turkish Constitutional Court defines the concept as everything that provides peace in society and the protection of the State and State organs; in other words, it contains all rules that are the basis of order in society, however defined [39].
Eksi claims that three points can be considered within the content of public policy. The first point is the basic rights and liberties that are guaranteed under the Turkish Constitution and international human rights conventions. The second point is the basic principles of law, and the third is the morality of Turkish society [5]. Dayinlarli adds a fourth point to this list by including the violation of international law [29]. Public policy is a set of rules protecting the basic structure and interests of the society in a specific country at a specific time. It is closely related to public interests, public conscience and morality [1,40]. Briefly, public policy exception aims to protect the interests of society. In English law, public policy defense is invoked if "some moral, social or economic principle so sacrosanct in English eyes as to require its maintenance at all costs and without exception" [34] (p. 123) is offended.
Based on a summary of all approaches, a violation of public policy can be defined as anything contrary to "the basic values of the Turkish law, Turkish morality, basic tendency of justice underlying the Turkish codes, general policies behind the Turkish codes, basic rights and liberties provided under the Constitution, general principles in the international arena, rules that depend on the good will principle of private law, general principles which represent the rules of morality and tendency of justice adopted by civil societies in common, the civilization level of the society, political regime, economical order of the society and basic human rights" [38] (p. 28).
It should be noted that public policy is a concept that can change over time as the values, beliefs, rights and wrongs of a society differ over time [8,37]. The reason behind these changes is the change in the interests of society, which lead public policy to adapt to changes in political, economic and social life [29]. Therefore, courts must consider the tendencies of public policy at the time a case is reviewed [15,28,37,41]. Public policy is a concept that also changes from one place to another; in other words, it changes from one country to another, and from one society to another [37]. This difference between countries shows that public policy tendency is national [28]. This is because each society's political, economic, social and legal structures constitute the domestic and international perspective of public policy. Each court is responsible for taking its domestic public policy into consideration [28,38,40].
Public policy is a concept that also changes depending on the subject matter. If it is the consequence of the enforcement of a foreign law that violates public policy, it may be opposed to public policy in one case, while in another case, it may not. For example, if a woman is divorced in a foreign country by the unilateral declaration of her husband (talaq divorce) against her will, this constitutes a violation of public policy. However, if the woman was willing to divorce and is now asking for recognition of her divorce, this might not lead to a violation of public policy [40].
Because public policy has an exceptional character [29,36], a foreign judgment can be enforced even if the subject of the judgment is related to public policy under Turkish law. For example, divorce is related to public policy in Turkish law, but enforcement of a foreign judgment regarding divorce might not be rejected because public policy is an exception. If the public policy has been accepted as a principle, then it will not be possible to enforce a foreign divorce judgment [38]. Public policy has a negative effect with regard to the enforcement of foreign judgments. If the foreign judgment violates Turkish public policy, by rejecting the enforcement, Turkish courts refuse to recognize a right that is obtained as a result of the foreign judgment [38].
When determining whether a foreign judgment is contrary to Turkish public policy, the judge should consider the consequences of enforcement of the foreign judgment in Turkey [2,15,32,35,37,42]. Turkish courts can analyze a violation of public policy on their own initiative. It is also possible to perform the necessary examination upon the claims of the parties [43].
A foreign judgment may go against public policy if it is given in a way that does not consider the best interests of the child, such as in a custody judgment that depends on ethnic origin, country of origin, or gender (such as giving custody directly to the mother or to the father), if the custody judgment prevents the establishment of a personal relationship between the child and the mother or the father who does not hold the right of custody, or if the judgment depends on religion, language or color [7,[13][14][15]44]. Judgments that terminate or limit the basic rights and liberties provided under the Constitution [30], that are contrary to the basic principles under the Constitution, that are given without considering the right of defense, or that approve immoral demands and relations are also contrary to public policy [2]. It is not possible to decide to enforce a foreign judgment if there is a finalized judgment by a Turkish court between the same parties on the same subject and for the same reason. This would lead to a violation of public policy. If there were reasons to refuse the judge under foreign law, such as if the judge was a close relative of one of the parties, public policy intervention may arise. If the foreign judgment is obtained as a result of fraud by one of the parties, this also constitutes a violation of public policy. It should be noted that Turkish judges have a right of discretion when determining whether a foreign judgment is contrary to public policy.
On the other hand, if the reason on which the judgment depends is not stated, this cannot be considered as a situation contrary to Turkish public policy [45]. It should be emphasized that if the law is not properly applied or a mistake is made during the interpretation of the concerned law [46], if the evidence is evaluated in a different way compared with Turkish law or if no judgment is given regarding personal relationships and custody, these cases do not constitute a situation contrary to Turkish public policy [2,4,7,40]. If the law applied by the foreign court includes different provisions compared to Turkish law, this also does not violate Turkish public policy. Unfortunately, the Turkish Court of Cassation refuses to give a judgment of enforcement when the enforcement of foreign joint custody judgments is requested because joint custody is not provided under the Turkish Civil Code (TCC) [47][48][49][50][51][52]. To clarify this issue, it is necessary to examine custody in Turkish law.

Custody in Turkish Law
Statistics from the Turkish Institution of Statistics show that the total number of divorces in Turkey were 126,164 in 2016, 128,411 in 2017, and 142,448 in 2018. "According to the estimation model, it is estimated that the divorce rate which was 1.67 per thousand in 2013 will be 1.93 per thousand by 2023" [20] (p. 45).
While divorce rates in Turkey are not high when compared to the rates in other countries, the increase in the number of divorce cases and weakening of family structure should be considered a national and social problem [21] (p. 7). Divorce rates were stable until 1996, subsequently decreased between 1997 and 2000, and began to increase once more after 2000 [21] (p. 5). It is possible to say that the lack of a serious increase in the number of divorce cases until the end of 1990's is due to the fact that divorce was not tolerated by the society. Lately, however, with the involvement of women in work life as a result of economic problems in families, the role of woman in family life has changed. This has consequently weakened the patriarchal structure of family relations. The increase in the number of divorce cases in Turkish society is proof of this situation [21] (p. 29). Furthermore, a rise in the educational level of spouses, women's rights becoming more visible, and the relative ease of the legal procedures for divorce, have also contributed to the increase in divorce rates [21] (p. 6).
Under the TCC (Article 166/3), spouses can get divorced based on mutual agreement (uncontested divorce). If consensual divorce is not possible, spouses can only get divorced by depending on the reasons stated in the TCC. These reasons are: adultery, attempted murder, a bad attitude or disrespectful behavior, committing a crime and living a dishonorable life, desertion, mental illness, irretrievable breakdown of marriage and separation.
A study conducted in Izmir, the city that has the highest divorce rate in Turkey according to 2009 statistics, with a total sample of 370 persons, including 202 women (55%) and 168 men (45%), found that when their opinions regarding grounds for divorce were asked, 69.3% of women and 32.1% of men stated "oral and/or physical violence" as a reason for divorce [21] (p. 55). Furthermore, a high rate of women also reported "oral and/or physical violence", "adultery", "bad habits" and "financial issues" as grounds for divorce, while "desertion", "interference of relatives" and "different points of view" were reported by men. Additionally, persons who stated violence as a ground for divorce are often the ones married unwillingly by way of arranged marriages. A high rate of spouses who got divorced because of violence need more psychological support when compared to others. These studies also showed that while women experience economic problems, problems with finding a place to live, and pressure from society and family after divorce, the rate of men claiming that they didn't experience any difficulty is quite high. Interestingly, according to the mentioned research, individuals who don't have a child face a higher level of emotional problems when compared to the ones that have children [21] (p. xii). When divorced parents are considered, 88.6% of custodial parents experienced emotional problems while 88.3% non-custodial parents made the same declaration [21] (p. 82); meaning that both custodial and non-custodial parents face emotional problems.
Another interesting issue regarding custody cases in Turkey is that the majority of women declared that they only want to take the custody of their children and nothing else at the courthouse [20] (p. 147). Therefore, it is possible to say that majority of mothers asked for unconditional custody of their children [20] (p. 148).
In Turkish law, parents hold custody jointly as long as the marriage continues. Although joint custody is not regulated under the TCC in cases of divorce and for children born out of wedlock, it is necessary to examine whether Turkish courts can rule for joint custody by interpreting the provisions of the TCC in a different way or by depending on international conventions that include rules regarding joint custody after divorce to which Turkey is a party. If the answer is yes, this will eliminate discussions of whether foreign joint custody judgments are contrary to Turkish public policy.

The Concept of Custody
The lexical definition of custody is to love, support, protect, look after and take care of someone and to assume responsibility and to manage the property and the person of a child [7,53,54]. The legal definition of custody is not included in the TCC. Some authors define custody as all the rights and obligations parents enjoy regarding the protection and representation of children exceptionally including legally restricted children who have reached the age of majority and their property [55][56][57][58][59][60][61][62][63][64].
Over time, due to changes in the social structure, the legal characteristics of custody have changed from the absolute authority of the father to rights and responsibilities that include the duties of the mother and the father to support the interests of the child [54,55,61,62,[65][66][67][68]. With this change, it is now acknowledged that custody is a social relationship rather than a relationship within the family. For this reason, the use of custody can be controlled, and if necessary, a judge can intervene [7,55].
Given that custody includes not only parental rights but also parental duties, it is understood that this institution serves the interests of the child and not the interests of the parents [57,67,69]. The main purpose of custody is to raise an independent and responsible child who is able to cope in real life [59,60,64,66,[70][71][72]. This function of custody also determines its scope: as the child grows older, the scope of custody narrows [54,67,73]. Therefore, the function and content of custody do not remain constant, but rather change over time. As the child under custody grows older and becomes mature, he/she naturally requires more freedom, and his/her opinions are taken into account more than when the child is younger (Article 339/III of the TCC) [54,70]. Pursuant to this provision, the child who has the mental capacity can use the opportunity to have a say over his/her own life regarding the decisions of the parents about education, social life, etc. [57].
Custody covers all of the parents' responsibilities toward the child. It creates a legal basis of the right to sovereignty over the child, care, the general, vocational, and religious education of the child, the child's representation and upbringing, management of his/her assets, safeguarding his/her interests and the naming of the child [53,57,60,64,72].
Since the right to custody is strictly personal, it cannot be transferred to another party by a legal action or inherited after death [56,57,62,64,66,68,69,74]. Additionally, the right to custody can neither be waived nor restricted by legal action [53,56,69,73].
Custody is a holistic concept, which is why it cannot be shared between the mother and the father based on time and duty [53,54,56,67,69,70]. When parents have joint custody, they enjoy complete custody simultaneously, equally and together [53,56,60,70,71,75]. However, it is possible for parents to leave the implementation of their decision on individual matters covered under custody to others [73], such as by making use of schools and teachers for the child's education. However, in such a case, the parents have an obligation to control and supervise.
On the other hand, it is debatable whether some of the powers and obligations arising from custody can be given to the mother and some to the father in cases of divorce or separation. Some authors argue that the powers and duties that accompany custody cannot be divided between parents and that some powers and duties cannot be assigned to the mother while others are assigned to the father [7]. In particular, it is argued that it is both difficult and harmful to share the powers and duties that custody offers with regard to the child's personal existence. Another opinion argues that in exceptional and important cases, custody can be divided by granting powers over the child's personal assets to one party and economic assets to the other [68].
Rules regulating custody pertain to public policy [7,68]. A child is born into a family, and he/she develops through the education given by the family. Societies transfer fundamental values to new generations within the family by means of custody. Therefore, it is beneficial for society to raise physically, mentally, emotionally and socially healthy children and to enable children to receive good education and to be raised in a healthy family environment. Thus, rules governing custody pertaining to public policy are imperative [67]. That is why Article 19 of the United Nations Convention on the Rights of the Child (UNCRC) stipulates that contracting states shall take all appropriate legislative, administrative, social, and educational measures to protect the child from all forms of physical or mental violence, injury or abuse, neglect or negligent treatment, and maltreatment or exploitation, including sexual abuse, while in the care of the parent(s).

Joint Custody in General
The first joint custody statute was passed in the State of North Carolina in 1975. "Joint custody has no fixed legal definition. It generally is perceived as consisting of two components: legal custody and physical custody. Joint legal custody entails both parents sharing responsibility and authority regarding the major decision concerning the child's upbringing. Physical custody refers to the child's living arrangements, time-share pattern, and responsibility for the child's day-to-day care" [76] (p. 204). In joint custody, both parents are granted equal and shared custody over the child [60,71,75,77]. Exercising custody jointly means the parents will jointly manage the child's care, education and upbringing [67,70]. That is why parents would have to consult each other and should not be able to make a decision by themselves on important matters, such as which school the child will go to, which country and city he/she will reside in, how he/she will be guided in terms of job selection or religious beliefs, or which treatments should be administered when he/she gets sick [63,67]. In the case of sole custody, the party entitled to custody may enjoy custody by himself/herself without consultation, and the other parent would not be able to intervene [60,75,77,78].
The advantages and disadvantages of joint custody are a debated issue in the doctrine. The following arguments indicate the negative consequences of the parents' use of joint custody after divorce.
After a divorce, there are still ongoing conflicts between parents. Therefore, it is argued that parents should not enjoy joint custody after a divorce on the grounds that they often continue the conflict between them over the child [78,79].
Another criticism directed at joint custody is that it is not possible to talk about a complete family because parents do not live together after the divorce. It is argued that the party who does not live with the child or has a less regular relationship with the child would have less insight about the child, and this would lead to problems [78].
It is noted that joint custody after divorce would eliminate the effect of provisions in the Turkish Constitution that protect the family [78]. For example, if non-married parents or parents who divorce are granted joint custody, the parties would not want to form a family or continue to be a family, resulting in an adverse impact on the family institution in the long run.
Despite the mentioned disadvantages, there are many advantages of joint custody as well. Studies reveal that parents who are granted joint custody after divorce have less conflict [55,60,63,76,77,80]. If one party is granted custody after divorce, the two parties may argue when the other party who does not have custody establishes a personal relationship with the child, or the noncustodial party may feel punished because he/she does not have custody and may punish the other party by not paying alimony [60,78]. Obviously, all of these situations will cause harm to the child.
In Turkish practice, custody of younger children is given to the mother. The basic reason behind this is that younger children need their mothers, who are often better suited to provide care as most of them are not employed. It should be noted that in cases where the mother is found to be living an immoral life, suffering from drug addiction, violent or uninterested in having custody, custody is given to father. The opinion of the child is important regarding custody decisions after 10-12 years of age [20] (p. 165, 166). "It is observed that many fathers are victims of not seeing their child because the implementation of child visit remains incompetent" [20] (p. 167). Maintaining the personal relationship between the child and the non-custodial parent is not only a children's right, but is a human right as well. It has been observed that this right is frequently violated in practice. There have been complaints filed with the Turkish Ombudsman about problems faced regarding the handing over of children. The applicant claimed that although it is possible to rule for joint custody under TCC, sole custody was given by the court, and ECHR Additional Protocol 7 Article 5, which provides equality among spouses regarding their personal relationship with children, which became part of Turkish legal system, is violated. This is also one of the requirements of UNCRC Article 9. The Turkish Ombudsman accepted the application, emphasized the need for amendment of the TCC, suggested that the Ministry of Family and Social Policies adopt a system of "family mediation" and establish of family meeting units to make sure that non-custodial parents will be able to come together with their children regularly [81]. Another dimension of these violations is related to international child abduction. 48 lawsuits were filed with the ECHR between 2000 and 2015 about child abduction, of which 6 were against Turkey. It should be noted that in 3 of the 6 cases (04. 12.2012 Ozmen v. Turkey, 03.05.2012 Ilker Ensar Uyanik v. Turkey and 13.10.2009 Ovus v. Turkey), the ECHR ruled for the violation of the right of respect to private and family life [82] (pp. 194-199). In this case joint custody could be a solution for preventing the mentioned undesirable consequences.
It has been shown that children who are under the joint custody of their parents are in a better psychological condition and overcome the trauma caused by the divorce more easily than children who are under sole custody [63,72,78]. In fact, it is suggested that a child's insecurities regarding the dissolution of the family diminish as he/she sees that his/her parents are people who can take care of him/her, can cooperate with each other and are trustworthy [78,80].
Joint custody in the case of divorce would allow parents to develop a sense of responsibility toward the child by preventing one of the parents from simply covering expenses without being involved in important matters and by enabling that parent to be an active part of the child's upbringing [63,64,78]. In addition, joint custody greatly reduces the child's sense of rejection and abandonment after divorce, eliminating the child's fear of losing one of his/her parents [79].
Bauserman reported that a series of meta-analyses showed that fathers who share custody have a "greater involvement with their children, greater satisfaction with custody, better psychological adjustment, and lower conflict with the ex-spouse (including relitigation)" (p. 466). On the other hand, mothers also have "better psychological adjustment (less parenting burden and stress), greater custody satisfaction, and lower conflict" [83] (p. 466).
Although it is argued that joint custody is the best solution for children, it is important to bear in mind that it is not the right solution for all families. When parents do not adopt a desired approach, children may be adversely affected by arguments between the parents during this new transition period [76,80]. This is why "the ideal divorced co-parenting relationship is a workable relationship between former spouses, open communication, concern for the child's best interests, sharing of parental responsibility, flexibility, trust, and availability of both parents" [76] (p. 219).
The judge must decide on the model of custody by evaluating the case. For example, if it is impossible for parents to come to an agreement or if one of the parents is violent, the judge must grant custody to a single party. Similarly, if one of the parents doesn't take care of the child, doesn't spend time with the child, sexually abuses the child, is alcohol or drug addicted, or negatively affects the confidence of the child by his/her insecure attitude, the judge shouldn't rule for joint custody [63] (p. 178). For the judge to rule on joint custody, the parents must be willing and must have the type of personality required for the exercise of joint custody. Legal rules must consider each country's own sociocultural conditions. There may be cases in some countries in which parents are unable to end conflict or to establish even the slightest relationship with each other for their children after divorce due to domestic violence and cultural elements, which may hinder joint custody from working smoothly [63].
In the event of divorce, the interests of the mother, father and child may conflict when determining a custody model. In such a case, the judge should uphold the child's best interests [7,63,76] and should rule on the model of custody that would best ensure these interests.
In an analysis of the perspective of Turkish parents on joint custody in the divorce process, Kiremitci studied 60 families that had at least one child under the age of eighteen and who had an ongoing consensual or contentious divorce in 2013 and 2014 in Family Courts at the Anadolu Courthouse in Istanbul. This study found that conflict between consensually divorced spouses was lower, consensually divorced individuals (53%) preferred joint custody more than those who experienced (27%) a contested divorce, and families with higher income adopted a democratic approach toward their children and were more likely to opt for joint custody [77]. In addition, individuals who participated in the study stated that they wanted to have equal rights over the child after divorce and that they wanted to enjoy the right of custody together for the child's moral education, physical and psychological health and treatment.

The Principle of the Best Interests of the Child
Because custody is an activity to develop a child's material and moral being, ensure his/her safety and develop his/her independent personality, it is an "obligation-right" that is granted to the parents for the best interests of the child rather than the interests of the parents [7,68,73]. In terms of exercising the rights and powers arising from custody, the interest of parents is limited to fulfilling their obligations arising from custody [73]. Therefore, it is not possible for the parents to make use of custody for any other interest or solely for their own interests.
The principle of the best interests of the child is the most important principle of child law [7,59,67,70]. The best interests of the child constitute the highest principle of equity to be taken into consideration when enforcing the provisions of child law and provides guidance when exercising the right of custody [70,71,76]. This principle must absolutely be taken into consideration in cases tried within the scope of child law. The main purpose in regulating custody in the case of separation or divorce is to safeguard the child's best interests and to secure his/her future [65]. This principle aims to ensure that the parents see the child as a subject with rights, respect his/her personality and ensure the multifaceted development of his/her personality [54,60].
Since the concept of the best interests of the child may differ in various aspects and cases, it is not possible to provide a comprehensive definition [59,60,62]. The concept in question is a flexible one that is open to the discretion of a judge and that must be shaped based on the characteristics of a specific situation [71]. At the same time, the fact that the concept cannot be defined allows it to be interpreted in line with psychosocial sciences and the changing and evolving nature of events and to further enrich its content [62].
Although the concept of the best interests of the child is not defined, it is possible to determine its content. Within this context, the concept of the best interests of the child involves the child's physical, mental, emotional, psychological and moral development (TCC Article 340) [70]. In addition, parents are obliged to provide physically and mentally disabled children with a general and vocational training that fits their skills and dispositions (TCC Article 340/II). The concept of the interests of the child also includes the child's social, legal and economic interests [59,60]. Although there are generally accepted criteria to identify a child's physical benefits, there are very few generally accepted criteria in a pluralistic society to identify a child's mental, psychological and moral benefits [59,60]. Within this framework, we can make use of basic principles, such as offering a better education or raising the child in a favorable, caring, and responsible environment that is dominated by a stable and continuous relationship [59,60]. In other words, when determining what the best interests of the child require, it is necessary to consider the needs of the child, the emotional link, the satisfaction of the basic needs of the child, and his/her education and protection [13]. In addition, special importance must be given to what the child has lived through and experienced and his/her emotions [13].
The principle of the best interests of the child is addressed to everyone involved with the child. It is not limited to the parents and can be decided for the child by judicial and administrative authorities, if necessary [59,60]. Above all else, this principle requires the parents and all relevant authorities to adopt a child-centered way of thinking in all their actions and decisions regarding the child.
Although there is no clear regulation on the principle of the best interests of the child in the TCC, Article 346 stipulates that a judge can take necessary protective measures for the child when his/her interests and development are in danger. In addition, the Articles 337/II and 339/I of the TCC on custody, identifies "the child's interest" as a determining criterion.
With regard to the protection of the child, Article 41/II of the Turkish Constitution stipulates, "The State shall take the necessary measures and establish the necessary organization to protect... children".
It is an imperative provision. This provision and the "social state principle" identified in Article 2 of the Constitution stipulates an obligation to protect and act in line with the child [7,62]. Furthermore, according to Article 41/III of the Constitution, "Every child has the right to protection and care and the right to have and maintain a personal and direct relation with his/her mother and father unless it is contrary to his/her high interests", which emphasizes that the child's interests are prioritized.

Rules Regarding the Use of Custody
The right to custody is only granted to the mother and the father [7,68,74]. It is possible for parents to enjoy the right of custody jointly or for either the mother or the father to have the right to custody according to specific circumstances. In this context, custody legally requires a genetic relationship [57,62,[67][68][69]. However, for parents to be granted custody, they should have sufficient mental capacity, they must have reached the age of majority, and they must not be placed under interdict [68].
Although a stepparent does not have the right to custody, he/she is obliged to support his/her spouse who has custody in performing his/her duties and caring for the child. In case of necessity, a stepparent may represent the child to meet his/her needs [68]. The only exception to the rule that only parents can have custody is adoption. With adoption, the rights and obligations of the parents pass to the adoptive parent, who has the right to custody over the adopted child.
As a principle, the custody of a child born in wedlock belongs to the parents (TCC Article 335), and the right to custody of the parents arises directly from the law at the time the child is born. Pursuant to Article 336/I of the TCC, parents enjoy joint custody through the course of their marriage. If joint life is terminated or separation occurs, the judge may grant custody to one of the spouses (Article 336/II). In the case of the death of one of the spouses, custody will be granted to the living spouse, and in case of divorce, custody will be granted to one of the spouses (Article 336/III). In the context of these provisions, it is important to emphasize that custody will be granted to one of the parents in case of divorce.
It is set forth in Article 337/I that custody of a child born out of wedlock shall only be granted to the mother at the time of birth. However, if the mother is a minor, is restricted or dead or if custody is taken from her, a judge may appoint a guardian for the child or entrust custody to the biological father in line with the child's interest (Article 337/II). There is no provision in the TCC stipulating a situation in which unmarried parents would like to share custody. This can obviously be criticized for being against the principle of equality provided under the Turkish Constitution. It is also against Article 9 of the UNCRC, which regulates the right of the child to not be separated from his/her parents against their will and Article 8 of the ECHR, which provides the right to respect for family life. It should be noted that because the joint adoption of a child is only possible for married couples, parents who live together outside marriage can't enjoy joint custody by adopting their child together [84] (p. 80).
It should also be noted that same-sex marriages, registered partnerships, or unregistered cohabitations are not legally recognized relationships in the Turkish legal system. According to the TCC (Article 134), a man and woman who want to get married should apply together to the marriage officer of the place one of them lives. This rule is a mandatory rule and prevents same-sex marriages in Turkey. Such partnerships are against the basic values and moral values of Turkish society [85] (p. 13). As a consequence, there is no provision in the TCC stipulating a situation in which same-sex partners would like to share custody.
As the TCC originates from Swiss law, it is important to examine amendments made in Swiss Civil Code (SCC) regarding joint custody. According to Swiss law, a child is under the custody of his/her parents until he/she reaches his/her majority (SCC Article 296/II). Under the measures of divorce or protection of the union of marriage, joint custody remains as a rule. However, if required for the interests of the child, the judge may grant custody to one of the parents (SCC Article 298) [70]. A legal provision introduced in 2000 to Swiss law enables divorced parents to enjoy joint custody. However, the fact that parents are not granted joint custody over their child born out of wedlock has been criticized on the grounds that it violates the non-discrimination principle set forth in Article 14 of the Convention for the Protection of Human Rights and Fundamental Freedoms (ECHR) [86]. Another provision introduced in 2014 allows for parents to enjoy joint custody, regardless of whether they are in wedlock. If parents want to enjoy joint custody over a child born out of wedlock, they need to file an official demand expressing their will [70]. So, if the parents are not married or if the child's father is unknown or the child's legitimization is determined by court ruling, a ruling on joint custody is granted, if possible. If not, a joint custody ruling may be granted later when both parents request this together. If the court upholds a paternity action, it shall rule on joint custody unless the mother retains sole parental responsibility or sole parental responsibility is assigned to the father to safeguard the child's interest (SCC Article 298c). If the court does not rule on joint custody when upholding a paternity action, the parents may subsequently apply to the Child Protection Authority to express their request for joint custody. On the other hand, if the father recognizes the child and makes the declaration at the same time that paternity is recognized, the declaration is made to the civil registrar or and application can subsequently be submitted to the Child Protection Authority (SCC Article 298a).
In Turkish law, custody can only be removed by court order as a result of the occurrence of certain conditions (Article 348) [57]. Therefore, a child cannot be taken away from his/her parents without legal grounds (Article 335). Custody lasts until a child reaches his/her majority. When a child reaches his/her majority, if a reason arises that requires the child to be restricted, the former custody regime is maintained rather than establishing new guardianship to protect the child (Article 335/II). There is no difference between a person under custody who is a minor and a person who has reached his/her majority but is restricted. If the child's parents are alive and married, the custody of a restricted adolescent child is granted to both of the parents, and they exercise custody together [68].
Parents who exercise the right to custody within marriage are obliged to jointly ensure the peace of the marriage and to jointly care for the upbringing, education and protection of their children (Article 185/II of the TCC). In addition, also pursuant to Article 322, "parents and children are obliged to help and respect one another and to show understanding towards one another as required to ensure the peace and integrity of the family".

The Issue on Whether a Judge Can Rule on Joint Custody in the Case of Divorce within the Framework of the Provisions of the TCC
While it is accepted for parents to share custody while their divorce case is ongoing or in the case of separation, it is still debatable whether joint custody after divorce is possible [56,63,64]. One opinion argues that it is not possible for parents to enjoy joint custody [69,74] after divorce, although some authors argue that joint custody should be possible under Turkish law [67,72,80,[87][88][89].
There are two fundamental provisions that form the basis for discussions on whether joint custody is possible after divorce. The first of these provisions is Article 182 of the TCC. The title of Article 182/I is "the discretion of the judge". This provision states, "When ruling on divorce or separation, the court regulates the rights of the parents and their personal relations with the child, after listening to the parents as much as possible and after receiving the opinion of the guardian and the guardianship authority if the child is under guardianship". Pursuant to the said provision, there are various views regarding whether it is possible for parents to enjoy joint custody of the child after divorce. According to one view, custody is granted to one of the parents after the divorce, and it is not possible for both parents to enjoy custody [57,64]. According to another opinion, when the meaning of the provision is considered, the judge, if possible, should rule for the rights and obligations of the parents and their relationship with the child after listening to the father and the mother. This is why it is not possible to reach a solution in which it is only possible to grant custody to one of the parents [87,89,90]. According to this view, the reason why a singular discourse was adopted regarding "the spouse to whom custody was not granted" in Article 182/II is that it is required to regulate the personal relationship between the child and the spouse to whom custody was not granted and to identify the alimony to be paid by that spouse since the provision was introduced to stipulate the possibility of entrusting the child/children to only one of the parties [89]. When custody is granted to both spouses, there is no need to decide on a personal relationship between the parents and the child, and there is no need for payment of alimony. Therefore, it is not correct to deduce from the said provision that custody must only be granted to one of the parents. It is also believed that the mentioned provision does not prevent custody, which is based on the judge's discretion, to be granted to both of the parents after divorce [80].
The second provision that should be examined is Article 336. According to Article 336/II, "If joint life has been terminated or a separation took place, the judge shall have the right to grant custody to one of the parents". There is no consensus in the doctrine on whether parents should enjoy joint custody or whether either of the parents should be granted custody in a case in which the spouses have ended their joint life (Article 197) or where a court has ruled on a de facto separation of the spouses (Article 171). According to an opinion, during a break from joint life or de facto separation, parents should not hold custody together; rather, custody should be granted to either of the parents to protect the child [91]. According to another opinion, it could be concluded from the contrary interpretation (a contrario) of the said provision that joint custody is possible in the event of an end to joint life or separation [68,80,89]. The said provision gives the judge discretion. Therefore, the judge may grant custody to one of the spouses while considering the interests of the child or rule on leaving the child under the supervision of one of the spouses while allowing them to enjoy joint custody [68].
Despite the termination of joint life or separation, custody can be executed by the parents together. In such a case, joint custody is considered a rule, while sole custody is an exception [68]. However, in cases of the termination of joint life or separation, it is inevitable that spouses experience more conflict and tension than in divorce. While it is set forth that both parents can enjoy custody provided that it is not contrary to the child's interests, it is inconceivable that joint custody would be absolutely denied after divorce regardless of the child's interests [60].
Article 336/III of the TCC stipulates, "The custody is granted to the living parent in the event of the death of one of the parents and to the parent, whom the child is left with, in the event of a divorce". The doctrine suggests that Article 336/III of the TCC is mandatory and that joint custody is not permitted [57,63]. While some authors who suggest this opinion [69] advocate for the accuracy of this ruling, others argue the opposite [66,88]. Hatemi and Kalkan Oguzturk argue that the aforementioned provision is appropriate and that the law provides a negative solution to the joint custody of the parents after the divorce [69]. According to Serozan, who claims that the mentioned provision is inappropriate, Articles 336 and 337, which do not provide joint custody, are against the principle of equality under the Constitution and to the right to form and develop the child's personality, the rights of the parents and the child's right "to not be separated from his or her parents" granted by the UNCRC (Article 9) [66,88]. Consequently, Serozan claims that the unconstitutionality of these provisions can be put forward by means of exception.
Similarly, arguing that Article 336/III of the TCC is not an appropriate provision, Kurt agrees with the opinion that if the conditions required for the proper functioning of joint custody after divorce exist, joint custody would serve the interests of the child better than sole custody. Therefore, she suggests that to adapt Article 336/III of the TCC, which clearly stipulates that custody be granted to one of the parties in case of divorce, to the conditions of the day, it is not possible to conclude that it allows for joint custody based on a contra legem interpretation [63].
Some authors suggest that Article 336/III of the TCC does not prevent the judge from ruling on joint custody, claiming that it is for the interests of the child in the event of divorce [60,67,80,89]. According to Kochisarlioglu, it is not correct to deduce that custody must be granted to only one of the parties in the event of a divorce based on the provision "In the event of a divorce..., custody shall be granted to whichever party the child is left with" [89] (pp. [88][89]. It is difficult to understand why a judge would not rule on joint custody when both parties request custody and when joint custody is in the interests of the child in the event of divorce. As is the case globally, divorce in Turkish law has started to gain a contractual character [89]. Article 166/III of the TCC stipulates that the parties must reach an agreement on the child's custody in consensual divorce cases and that a judge must legitimize this agreement. In this context, if custody is agreed upon by the parties and this arrangement is not against the interests of the child, then the judge should not reject this arrangement [80,87,89]. Today, there is a prevailing opinion that the power of judges regarding custody must be reduced and that these problems should not be related to public policy but should be problems that are predominantly or related to individual will [54,89]. The first joint custody ruling after divorce was made on 27 May 2009, by theİzmir 4th Family Court in a consensual divorce case upon the request of the parties and on the grounds that the best interests of the child required joint custody [60]. Joint custody must be the rule and sole custody the exception [89]. In fact, even if the parents do not agree on joint custody and, in a specific case, it will serve the best interests of the child, the judge should still rule on joint custody [72].
Arguing that Article 336/III of the TCC does not prevent a decision on joint custody in the case of divorce, Oztan suggests that different methods of interpretation should be adopted to identify the meaning of the said provision and that the commonly used time-related objective interpretation method could be adopted [57,87]. According to the author, it is clear that the interpretation of the words of the Article does not correspond with its ratio legis when this interpretation method is used. The objective is the best interests of the child; however, the means have changed. Today, joint custody shared by both parents may be of greater interest for the child [60,68,87]. Within this context, it is argued that "restriction on purpose" could be used by accepting that there is an implicit gap because the letter and purpose of the provision set forth in Article 336/III do not comply with one another [87]. In this case, it is accepted that there is a legal gap in the TCC and that the judge should exercise his/her power to fill the gap in favor of the child [67].
According to an opinion, joint custody should be the rule in cases of divorce and sole custody should be exception that can be ruled for in cases of conflicts between parents. On the other hand, some authors advocate for sole custody to be the principle and a right of discretion should be given to the judge to rule for joint custody if it serves the best interests of the child. The final approach, with which we also agree, is that there shouldn't be any distinction between joint custody and sole custody as being the principle or the exception; instead, judge should rule in favor of the custody model that serves the best interests of the child [63] (p. 169,170).
To conclude the discussions presented above, Articles 182 and 336 of the TCC should be amended by taking into consideration the hesitations in the doctrine and court practices and developments in current laws and a regulation allowing divorced parents to enjoy joint custody unless the best interests of the child require otherwise [67].

Enforcement of Foreign Judgments in Turkish Law
After studying how custody is regulated in Turkish law, it is necessary to explain the enforcement procedure in Turkish law to clarify the discussions regarding the enforcement of foreign joint custody judgments.
When a foreign judgment on custody is obtained, how can it be enforced in Turkey? In other words, which rules will be applied, and what are the conditions required under these rules? In the Turkish legal system, if Turkey is party to an international convention regarding the recognition and enforcement of foreign court judgments, the convention will have priority compared to the Turkish Private International Law and Procedural Law Act [87]. Therefore, if a case is within the scope of the 1996 Hague Convention or the 1980 European Convention, provisions regarding the recognition and enforcement of these two conventions will be applied; if not, provisions of the Turkish Private International Law and Procedural Law Act will be taken into consideration [15,17]. Priority is given to international conventions because of the principle of pacta sund servanda and the international prestige of the country in international society. If there are both bilateral and multilateral treaties to which the state is party, both will be applied unless there are contrary provisions in these documents. If the mentioned treaties are not in conformity, the principle of lex specialis derogat generali will be taken into consideration. In that case, the treaty, including special provisions regarding the issue, will have priority [3,7]. Generally, international conventions include more simple conditions than the Turkish Private International Law and Procedural Law Act. If the international convention includes harsher conditions for the judgment of enforcement compared to the Turkish Private International Law and Procedural Law Act, the plaintiff can depend on the conditions in favor of him that are provided under the Act [2]. Under the mentioned Act, it is possible to study the conditions required for the enforcement of foreign judgments by dividing them into preconditions (Article 50) and basic conditions (Article 54). Before examining the conditions required for enforcement, it is necessary to state that the procedure for enforcement can also be followed by parties who are not Turkish citizens as long as they have a legal interest (Article 52) to enforce the foreign judgment [92].
Preconditions regarding the enforcement of foreign judgments require the foreign judgment to be a judgment pertaining to civil suits given by foreign courts. Article 1 of the European Convention provides that a decision given by a judicial or an administrative authority relating to custody can be subject to recognition and enforcement under the Convention, unlike the Turkish Private International Law and Procedural Law Act, which requires the decision to be given by a court. In some countries, such as Denmark and Japan, decisions relating to custody are given by administrative authorities [7]. If a country is party to the European Convention, Turkey should recognize or enforce foreign decisions on custody given by the administrative authorities of that country [2,93]. The law of the country where the judgment is given determines whether it is a court decision. It should be emphasized that sometimes foreign judgments that are considered court decisions in the country of origin might not be accepted as a court decision in the country where recognition and enforcement has been requested. For example, if the foreign law considers the decision of a religious institution to be a court decision, this might not be accepted by the country of recognition and enforcement [2]. It should be noted that under Turkish law, custody is one of the issues of family law, which is a sub branch of civil law. This means that foreign judgments regarding custody can be enforced because they are outcomes of civil suits.
The second precondition requires the foreign judgment to be final under the laws of the foreign court. The European Convention Article 7 provides that "a decision relating to custody given in a Contracting State shall be recognized and where it is enforceable in the State of origin, made enforceable in every other Contracting State". This means that a decision might not be final, but if it is enforceable in the state of origin, it could be enforceable in all other contracting states. Although the judgment that requires enforcement judgment must be final, decisions regarding custody do not constitute final judgment and can be amended depending on changing conditions. It is also necessary to state that this does not affect the procedure of giving enforcement judgments [7].
Basic conditions required for the enforcement of judgments are regulated under Article 54 of the Turkish Private International Law and Procedural Law Act. The court that has jurisdiction shall give the enforcement of judgment provided that "there exists an agreement based on reciprocity between the Republic of Turkey and the State where the judgment was given or a provision of law or actual practice enabling the enforcement of judgments given in Turkish courts at that state". Depending on this provision, the judge is obligated to investigate whether there is an agreement between the Turkish Republic and the foreign country regarding the enforcement of judgments [79]. If there is no such agreement, the judge should investigate the existence of statutory provisions regarding the enforcement of foreign judgments in the respective state. Finally, if no such provision is found, the judge will consider the de facto situation in the respective country regarding the enforcement of judgments [13,14]. If the judgments of Turkish courts are enforced in the respective country, the existence of the condition of reciprocity will be accepted [2,8,15,17,42]. On the other hand, although there is an agreement or a statutory provision, if a Turkish court decision has never been enforced because of the lack of such a request, the existence of the condition of reciprocity should be accepted [9]. It should be emphasized that if the conditions required for recognition and enforcement are harsher than those provided under Turkish law, the existence of reciprocity will not be accepted [2,9]. Some authors claim that reciprocity should not be a condition for the enforcement of foreign judgments, at least in cases of family law issues, because it is only a political condition that does not serve justice [7]. It is possible to say that the condition of reciprocity serves the foreign policies of states and protects their political interests [38,43]. If there is an international convention regarding the recognition and enforcement of foreign judgments to which Turkey is a party, for all contracting states, the condition of reciprocity is accepted as satisfied under the Turkish Private International Law and Procedural Law Act. Therefore, if a judgment given in a state party is requested to be recognized and enforced in Turkey, Turkish courts will not investigate the existence of the condition of reciprocity.
According to the Turkish Private International Law and Procedural Law Act Article 54/1/b, if "the judgment is given regarding an issue that is not within the exclusive jurisdiction of Turkish courts or not given by the court of a state granting itself jurisdiction although it does not have a genuine relationship with the subject of the case or the parties, on the condition that the defendant raises an objection to that effect" can be enforced. There is no provision about exclusive jurisdiction under the European Convention. The judge is under an obligation to investigate whether the case on which the foreign court has decided is under the exclusive jurisdiction of Turkish courts. There is no provision under the Turkish Private Law and Procedural Law Act that defines issues within the exclusive jurisdiction of Turkish courts. Therefore, when deciding whether an issue is within the exclusive jurisdiction of Turkish courts, the expression and the purpose of adoption of the rule regarding the jurisdiction of Turkish courts must be taken into consideration [2,8]. Turkish courts do not have exclusive jurisdiction regarding custody suits [3,7,15,17,79,94]. If the defendant raises an objection, Turkish courts should consider whether the foreign judgment is given by the court of a state that grants itself jurisdiction although it does not have a genuine relationship with the subject of the case or the parties.
Before studying violation of the public policy as a condition that prevents the enforcement of foreign judgments, one more condition under the Turkish Private International Law and Procedural Law Act required for the enforcement of foreign judgments must be examined. Turkish courts will give a judgment of enforcement if the person against whom enforcement is requested was not duly summoned pursuant to the laws of that foreign state or to the court that has given the judgment or was not represented before that court or if the court decree was not pronounced in his/her absence or by a default judgment in a manner contrary to these laws and the person has not objected to the exequatur based on the foregoing grounds before the Turkish court. As can be understood from Article 54, there is a need for the objection of the defendant to be able to consider whether the defendant's right to defense has been observed by the foreign court. It is believed that because the right to defend is a very serious issue, it could have been investigated automatically by the court. Judgments given without observing the right to defense do not reflect justice and judicial truth. It should also be emphasized that if the defendant's right to defense is not respected by the foreign court and the judge realizes the situation, he could reject the request for the judgment of enforcement by depending on public policy reservation. In a case reviewed by the Court of Cassation (Second Chamber of the Court of Cassation, E.2009/8144, K. 2009/12603, 25 June 2009), the plaintiff filed a claim regarding divorce in the city of Ghent in Belgium and showed the address of his wife in a foreign country, and the case was concluded against the wife/the defendant. When the husband asked for recognition and enforcement of the judgment of divorce, the defendant made an objection, and the court refused to recognize and enforce the foreign judgment because the defendant's right to defense was not respected by the foreign court [95].

Approach of the Turkish Court of Cassation Regarding Public Policy Exception in Enforcement of Foreign Joint Custody Judgments
According to the Turkish Private International Law and Procedural Law Act Article 54/1/c, for the enforcement of a foreign judgment, "the judgment should not be manifestly contrary to public policy". The requirement of being manifestly contrary to public policy, which limits the intervention of public policy and aims to prevent arbitrariness or misuse, is the consequence of courts' abuse by frequently depending on public policy as a remedy to prevent the enforcement of foreign judgments [9]. It should be noted that, as stated above, there is no direct provision regarding public policy under the European Convention, which has priority when compared to the Turkish Private International Law and Procedural Law Act. On the other hand, because the 1996 Convention does not provide automatic enforcement of decisions and requires the satisfaction of the rules of the requested state, public policy will be considered under the Turkish Private International Law and Procedural Law Act.
According to the Court of Cassation, a judgment including the execution of something that is manifestly contrary to legal and conscientious basic principles that are necessary for peaceful and compatible continuation of the society violates public policy [96]. Although the Court appropriately defines the concept of public policy, as stated above, there are inappropriate decisions of the Court that reject the request of enforcement if the foreign judgment includes joint custody. In one case, the Court refused to give a judgment of enforcement because the foreign court decided upon joint custody by applying German law, which is against the TCC [48]. This situation shows that the Court considers rules of foreign law that are different from Turkish law as contrary to the public policy and ignores the exceptional character of public policy [97]. In other words, foreign family law judgments that depend on the law of a foreign country must also be in conformity with Turkish law to be recognized or enforced [98]. This also means that the Court applies the public policy exception as if it is a mandatory rule [44]. Obviously, this has been criticized [35,79]. It is not possible for the court to decide upon enforcement to analyze whether the law applied by the foreign court is in conformity with Turkish public policy. Within the framework of the request for enforcement, refusal is only possible if the legal consequences of the enforcement are contrary to public policy [45]. With the mentioned decision, the provision of TCC Article 336/III, which gives the judge the authority to entrust custody to one of the spouses in the case of divorce, is accepted as a provision "directly linked to public policy both domestic and international cases" [94] (p. 314) by the Turkish Court of Cassation.
It is obvious that the attitude of accepting mandatory domestic rules within the concept of public policy for legal conflicts with foreign elements is not feasible. Otherwise, it becomes impossible to apply foreign law in cases of family law suits. It should also be emphasized that raising the public policy exception depending on differences between the legal provisions of two countries will prevent the functioning of private international law. This is also against the exceptional character of public policy and the necessity of considering public policy in each specific case by examining the consequences of the application of foreign judgment [44].
In 2004, the same attitude of the Court was observed, but this time, the decision was given by the majority, and the dissenting vote was interesting: "one can talk about public policy exception if the foreign judgment is against the basic rights and liberties determined under the Constitution, basic principles accepted in international law, fair trial and right of defense, morality and principles which the state cannot give up and constitute the basis of Turkish legal system. This has been expressed in Private International Law and Procedural Law Act by underlining that the foreign judgment should be manifestly contrary to public policy. If the foreign law ignores the mandatory rules of the Turkish law, this does not automatically cause violation of Turkish public policy" [99]. What requires the intervention of public policy is the violation of "the basic legal principles and inalienable state policies behind the substantive Turkish law...not the substantive rules of Turkish law" [99]. It is obvious that rules regulating custody in domestic law might be related to public policy [17] and mandatory, but this does not require the intervention of public policy in private international law. Nomer claims that the judge has the right of discretion when deciding to whom custody will belong after divorce by considering the relationship of the spouses and, especially, the best interests of the child. The judge is required to give custody to one of the parents (Article 336 of the TCC). Therefore, it is not possible to say that foreign joint custody judgments breach the basic legal values of Turkish family law and are manifestly contrary to public policy. Similar to Nomer et al.'s claim that a rule that is related to public policy in domestic law does not have to be related to public policy in private international law [35]. Foreign joint custody judgments do not require public policy intervention; on the contrary, they serve the principle of the best interests of the child, which is a generally accepted principle. Canyas emphasizes that it is not appropriate to refuse the enforcement of a foreign judgment by depending on public policy only because the foreign judgment is different from a rule that is not mandatory and that gives the judge discretionary power [94].
Divorce only terminates the bond of marriage between the spouses; it does not end parenthood. Therefore, the automatic termination of the custody of one of the spouses as a legal and social choice of the lawmaker and a different attitude within foreign law should not lead to the intervention of public policy. It is stated that joint custody would not function properly because the spouses will continue the animosity between them after divorce. Obviously, this has nothing to do with the basic values of Turkish society or the essential principles of Turkish law. On the other hand, the exercise of joint custody in a way that is contrary to the best interests of the child is not only common for divorced spouses. According to the TCC, spouses can exercise custody jointly in marriage, but the Code provides that if the development and interests of the child are in danger and the father and mother cannot find a solution or do not have sufficient power to eliminate the danger, the judge should take necessary precautions to protect the child. Such precautions may include the termination of custody. This explanation shows that there are enough remedies under Turkish law to eliminate objections regarding joint custody. The doctrine also claims that joint custody could be an ideal solution in cases of divorce because it serves the best interests of the child, which is a principle provided under all international conventions to which Turkey is also a party. In cases of divorce, there is no difference between the mother and the father regarding their responsibilities to and love for the child [35,97]. This is not contrary to the basic principles of Turkish family and child law. Therefore, it is not possible to refuse the enforcement of foreign joint custody judgments unless they are contrary to the best interests of the child.
The most important consideration when determining the recognition and enforcement of judgments regarding custody is the best interests of the child [16,44,93,94]. In other words, the best interests of the child determine the scope of public policy in Turkish private international law regarding the enforcement of foreign custody judgments. Consequently, any foreign judgment in which the best interests of the child are not considered should be carefully examined with regard to public policy. The mentioned examination requires serious and deep study at the stage of recognition and enforcement because it is not as easy at this stage compared to the position of the court in the first instance. It is obvious that when examining whether the foreign judgment serves the best interests of the child, the judge should, to some extent, check the pertinence of the foreign judgment. This seems contrary to the attitude that there is no way to control the pertinence of the foreign judgment. For this reason, only the provisions and reasons included in the judgment can be examined when determining whether the judgment is contrary to public policy.
At this stage, it is necessary to examine the principle of no révision au fond. This principle refers to the prohibition of checking the value of the judgment by considering the legal rules applied and events evaluated by the foreign court. Revision au fond is not possible under the Turkish Private International Law and Procedure Law Act, although this is not expressly stated. Therefore, Turkish courts can only examine whether the conditions of enforcement exist. It is not possible for the judge to review the foreign judgment; in other words, an examination of the procedure applied and the factual and legal findings of the foreign judgment is prohibited [4,5,9,35]. For example, if the foreign court, when considering the best interests of the child, gives custody to the mother, it is not possible for Turkish courts to reject enforcement due to the belief that custody should have been given to the father. This leads to a review of the foreign court's right of discretion, which is against the concept of no revision au fond. This principle is also accepted in case law [100]. It should be noted that as a result of the principle that prevents review of the foreign judgment by the requested court, a foreign judgment can be recognized and enforced even if domestic courts would have decided differently. Gokyayla claims that if the law applied to the case for which judgment is requested to be enforced violates an indispensable principle of Turkish law, strict obedience to no revision au fond may not properly serve to protect the interests that are protected with the public policy exception. Therefore, to decide whether a joint custody judgment serves the interests of the child "the Turkish judge may analyse the merits of the case as an exception to the prohibition of revision au fond" [94] (p. 324). In addition to the principle of the best interests of the child, nondiscrimination, respecting and providing for the child's basic right to live and considering the opinion of the child if necessary are other basic principles that could be considered in relation to public policy [97].
There are also decisions of the Court of Cassation in which public policy is properly applied and the judgment of enforcement is not given because it does not serve the best interests of the child. The Court of Cassation can consider the UNCRC and state that when a foreign judgment is given, if the wishes of a child who has sufficient mental capacity are not considered during the case, this is manifestly contrary to public policy. On the other hand, if the foreign court only considered the agreement between the mother and the father regarding custody without examining the best interests of the child, this judgment is contrary to public policy, and the judgment of enforcement should not be given [101]. When a long time has passed after the foreign judgment was obtained, the requested court may refuse to give the judgment of enforcement because the foreign judgment no longer serves the best interests of the child [41,102].

Joint Custody in International Conventions that Turkey is Party to and Recent Court Practices
According to Article 90/V of the Turkish Constitution, "International agreements duly put into effect have the force of law. No appeal to the Constitutional Court shall be made with regard to these agreements, on the grounds that they are unconstitutional. In the case of a conflict between international agreements, which are duly put into effect, concerning fundamental rights and freedoms and the laws due to differences in provisions on the same matter, the provisions of international agreements shall prevail". The provisions of an international agreement that are made in a concrete and clear manner to serve as grounds for a ruling can be directly enforced as an act.
The UNCRC, which is adopted by Turkey in 1995, recognizes the direct applicability of regulations on classical rights and freedoms [55,60]. In particular, it is noted that the principles of the best interests of the child and taking his/her opinion (hearing him/her) into consideration are directly applicable [55]. Pursuant to Article 3 of the UNCRC, "In all actions concerning children, whether undertaken by public or private social welfare institutions, courts of law, administrative authorities or legislative bodies, the best interests of the child shall be a primary consideration". In this context, as in all matters concerning children, the best interests of the child are the primary consideration in establishing the custody relation between the parents and the child. Also the second principle of the 1959 Declaration of the Rights of the Child stipulates that in the enactment of laws for the child, the best interests of the child shall be the paramount consideration [60,62].
As set forth in Article 12 of the UNCRC, a child who is capable of forming his or her own opinions must be granted the right to express those opinions freely in all matters that affect the child. Within this context, the Convention requires states' parties to ensure that every child who is capable of forming opinions can freely express his/her opinions on any matter of concern to him/her and that the child's opinions are taken into consideration depending on his/her age and maturity [54]. When making custody arrangements, to ensure the safety and well-being of a child who is capable of forming his or her own opinions, the child must be able to express his/her views, and his/her wishes must be taken into consideration if conditions allow.
On the other hand, pursuant to the European Convention on the Exercise of Children's Rights, which is adopted by Turkey in 2001, a child considered by internal law to have sufficient understanding is granted the right to be consulted and express his/her opinion in the case of proceedings before a judicial authority that affects him or her (Articles 3 and 6).
The rulings of the Court of Cassation highlight Articles 3 and 12 of the UNCRC and Articles 3 and 6 of the European Convention on the Exercise of Children's Rights and note that when making custody arrangements, the principle of the best interests of the child must definitely be taken into account and that a child considered by domestic law as having sufficient understanding must be granted the right to be consulted and express his or her views in the case of proceedings affecting him or her [98,[103][104][105][106].
On the other hand, Article 18 of the UNCRC emphasizes that both parents have common responsibilities for the upbringing and development of the child. Therefore, it is clarified in the Convention that parents are the primary right-holders and responsible individuals for the upbringing of their own children [55]. Based on these provisions, it is concluded that in the case of divorce, joint custody should be granted unless it is contrary to the interests of the child [63]. The mentioned provision can also be grounds for the enforcement of foreign joint custody judgments.
Another provision that can be used as grounds for the enforcement of foreign joint custody judgments is Article 6 of the Recommendation No. R (84) 4 of the Committee of Ministers of the Council of Europe on "Parental Responsibilities". According to this provision, in the event of the dissolution of a marriage, the competent authority should rule on joint custody provided the parents' consent is not contrary to the interests of the child.
Turkey ratified Protocol No. 7 of the ECHR, as amended by protocol No. 11, which was signed on 14 March 1985, by publishing it on the Official Gazette No. 6684 on 25 March 2016. Pursuant to Article 8 of the ECHR, everyone has the right to respect for his/her family life. It is suggested that international regulations that exclude the possibility of granting joint custody to parents after divorce would be contrary to Article 8 of the ECHR on the grounds that both parents and children can enjoy this right and that the family life between a child and his parents continues even after a divorce [61]. In the cases of Zaunegger v. Germany (22028/04, 3 December 2009) [107] and Sporer v. Austria (35637/03, 3 May 2011) [108] tried by the European Court of Human Rights, the Court found rulings on the granting of custody of children born out of wedlock to the mother and on joint custody without the consent of the mother to be against Articles 8 and 14 of the ECHR.
On the other hand, pursuant to Article 5 of the Protocol, "Spouses shall enjoy equality of rights and responsibilities of a private law character between them, and in their relation with their children during marriage and in the event of its dissolution". Therefore, as long as it is not contrary to the child's safety and interests, custody must be granted jointly to the parents [58,63,65]. Because this Protocol is a treaty on fundamental rights and freedoms, it became part of domestic law without the need for an additional legal regulation pursuant to Article 90/V of the Constitution. The provisions of the TCC on custody and Article 5 of the Protocol contradict one another. In this case, because parents' right to custody is related to fundamental rights and freedoms, Article 5 should prevail [63,79,109,110]. Therefore, the provisions of the TCC stipulating that a judge can grant custody to one of the spouses in the case of divorce or separation are implicitly abolished upon the adoption of the Protocol in question [63,65,78].
Therefore, Turkish courts can decide upon joint custody by considering the child's relationship with his/her mother and father, the relationship between the mother and the father, the reason for divorce and similar psychological and sociological elements and the will of the spouses [16,41,97]. If all these elements serve the best interests of the child, joint custody could be the best solution. If it is possible for Turkish courts to decide upon joint custody, it is meaningless to refuse to enforce foreign judgments that provide joint custody by depending on the public policy exception. This means that when deciding to enforce a foreign joint custody judgment, the judge should consider the child's best interests; this has a constitutional basis. Of course, if the enforcement of the joint custody judgment is against the child's best interests, public policy intervention will come to the scene because the situation is against a constitutional principle [94].
Issues related to joint custody in the case of divorce have been brought before the Court of Cassation with regard to either the application of the foreign law that allowed joint custody in the case of divorce or the enforcement of custody judgments of foreign courts regarding divorce. As discussed above, the Court of Cassation rejected joint custody after divorce in its jurisprudence until 2017 based on the fact that provisions that regulate custody after divorce were mandatory and related to public policy.
In the 2017 decision of the Court of Cassation (2nd Chamber of the Court of Cassation, E. 2016/15771, K. 2017/1737, 20.02.2017) [111], a foreign law regarding joint custody was not considered an issue contrary to public policy. This led to an expectation for a change of the existing attitude.
According to the mentioned judgment, although the case was about the conflict of laws, the Court of Cassation stated that joint custody is not against Turkish public policy. The plaintiff was an English citizen whose child was born outside marriage and who was requesting joint custody.
The plaintiff filed a lawsuit to the court of first instance. The court applied Article 17 of the Turkish Private International Law and Procedural Law Act and decided to apply English law because it was the national law of the child, the father and the mother. According to the English legal system, it is possible to decide upon joint custody when a child is born out of wedlock. The court of first instance rejected the father's demand regarding joint custody by stating that it was contrary to Turkish public policy. Then the father filed a lawsuit to the Court of Cassation for appeal. The Court considered whether joint custody is violating the Turkish public policy. As stated above, the Court of Cassation decided that joint custody is not manifestly contrary to Turkish public policy. The ground for the judgment is Article 5 of the Additional Protocol 7 of the European Convention on Human Rights. The new tendency of the Court of Cassation [112] will prevent the Republic of Turkey from being punished by the European Court of Human Rights when joint custody judgments are not recognized and enforced, especially in cases of judgments given in EU countries. Sweden, Spain, France, England, and Germany are some of the countries that give joint custody judgments. If the attitude does not change after the 2017 decisions, when a joint custody judgment comes from one of the mentioned states, the Republic of Turkey will face a problem. Unless the joint custody judgment does not serve the best interests of the child, it should be enforced [113].
It should be noted that after the mentioned decision of the Court of Cassation on unmarried parents' ability to enjoy joint custody, district courts also began to rule on joint custody if both parents request it and when it is required by the best interests of the child [56,75].

Conclusions
It is possible to say that joint custody serves the interests of the child better than sole custody if the parents agree to hold custody together and the conditions required for the proper functioning of joint custody exist in the case of divorce. Within this framework grounds for divorce must be carefully examined to make sure that joint custody will operate properly. It should be underlined that to avoid depriving the child of the custody of one of the parents or depriving one of the parents' enjoyment of the use of custody, if the necessary conditions are satisfied, joint custody will be in the best interests of the child. That is why it is suggested that instead of joint custody or sole custody being the principle under the TCC, right of discretion must be given to judges to rule for the best custody model in each specific case.
As stated above, the ECHR, UNCRC, and European Convention on the Exercise of Children's Rights provide that it is possible to rule for joint custody if it serves the best interests of the child. According to the Turkish Constitution, the mentioned conventions became part of domestic law, and if they contradict national acts, these conventions will have priority. Therefore, Turkish courts must consider the provisions of these international documents when determining custody of a child after divorce or in cases of children who are born out of wedlock and rule on joint custody by eliminating the provisions of the TCC regarding custody. Otherwise, Turkey will face lawsuits filed to ECHR against Turkey for violating human rights especially.
It is obvious that public policy is a generally accepted exception regarding the enforcement of foreign judgments. Although it is difficult to define the concept of public policy, it may arise mainly if the foreign judgment violates the basic values of Turkish law, Turkish morality, and the basic rights and liberties provided under the Constitution. Within this framework, differences between foreign law and Turkish law are not adequate grounds for refusing the enforcement of foreign judgments. The Turkish Court of Cassation refused to give an enforcement judgment regarding foreign joint custody judgments because joint custody is not provided under the TCC and because custody is related to public policy. It should be noted that public policy must be narrowly interpreted in private international law.
The exceptional character of public policy is another important issue that must be considered. What is important is not whether the foreign law applied by the foreign court is in conformity with Turkish law but rather the consequences of the enforcement of the foreign judgment. If such consequences are against Turkish public policy, the request for enforcement can be refused. From the decisions of the Court of Cassation, it is obvious that the public policy exception is applied improperly. In 2017, the Court of Cassation abandoned this improper tendency and declared that joint custody is not repugnant to Turkish public policy. Finally, it should be emphasized that the rulings of chambers of the Court of Cassation, as in the case of the 2017 decisions, are not binding unless ruled by the Unifying Jurisprudence of the General Assembly of Court of Cassation which aims to unify different interpretations of chambers on a specific issue.
Author Contributions: A.A. and E.K.R. designed the concept and outline for the article; A.A. analyzed the legal documents and court decisions and reviewed literature from the private international law perspective; E.K.R. analyzed the legal documents and court decisions and reviewed literature from the civil law perspective. A.A. and E.K.R. wrote and edited the manuscript. All authors have read and agreed to the published version of the manuscript.