US Family Law
Constitutional Framework
Family law in the United States is principally a matter of state law, reflecting the federal structure of the Constitution and the Tenth Amendment’s reservation of powers not delegated to the federal government to the states. Each of the fifty states maintains its own family code, subject to constitutional constraints imposed by the Supreme Court of the United States, which has recognised certain fundamental rights touching upon marriage and family life under the Due Process Clause of the Fourteenth Amendment.
The Supreme Court’s modern family law jurisprudence begins with Loving v Virginia, 388 US 1 (1967), in which the Court unanimously struck down Virginia’s anti-miscegenation statute prohibiting interracial marriage. Chief Justice Warren held that the freedom to marry is a fundamental right implicit in the concept of ordered liberty, and that racial classifications in marriage laws were subject to strict scrutiny and could not survive. Loving established marriage as a fundamental right under the Due Process Clause, a principle that the Court reaffirmed in Zablocki v Redhail, 434 US 374 (1978), invalidating a Wisconsin statute requiring non-custodial parents to obtain court approval before marrying, and in Turner v Safley, 482 US 78 (1987), striking down a prison regulation restricting inmate marriages.
The fundamental right to marry reached its fullest expression in Obergefell v Hodges, 576 US 644 (2015), in which Justice Kennedy, writing for a 5–4 majority, held that the Fourteenth Amendment requires states to license and recognise same-sex marriages. The Court identified four principles underlying the constitutional protection of marriage: the individual autonomy inherent in the choice of whom to marry; the unique association of marriage with same-sex couples — indeed, with one’s most intimate relationships; the protection of children and families; and marriage’s central role in the legal and social order. Obergefell rendered unconstitutional all state laws and constitutional amendments limiting marriage to opposite-sex couples, effectively nationwide marriage equality.
Requirements for a Valid Marriage
Each state prescribes the formal requirements for a valid marriage, though certain common elements obtain across all jurisdictions. A marriage licence must be obtained from the state or county clerk’s office before the ceremony. Both parties must appear personally, provide proof of age and identity, and pay the requisite fee. Some states impose a waiting period between issuance of the licence and the ceremony. Blood tests, once common, have been eliminated in most states.
The ceremony must be conducted by an authorised officiant, which may include judges, justices of the peace, clergy, and in some states, ship captains or other designated persons. Most states require at least one witness. After the ceremony, the officiant returns the signed marriage licence to the issuing authority for registration.
A critical distinction exists between ceremonial marriage and common-law marriage. Common-law marriage arises when a couple (i) agree to be married, (ii) cohabit, and (iii) hold themselves out to the public as married, without any formal ceremony or licence. Once a minority of states recognised common-law marriage; today it persists in a shrinking number of jurisdictions including Colorado, Iowa, Kansas, Montana, Rhode Island, South Carolina, Texas, and Utah. Most states have abolished it. Common-law marriages validly contracted in a state that permits them must be recognised as valid under the full faith and credit principles of the United States Constitution.
Divorce
The law of divorce in the United States underwent a transformation beginning with California’s Family Law Act of 1969, which introduced the first pure no-fault divorce system in the common law world. By 1985, every state had adopted some form of no-fault divorce, and by 2010 all fifty states offered a pure no-fault option — divorce without any requirement of proving fault.
Under the modern no-fault regime, the sole ground for divorce is the irretrievable breakdown of the marriage, expressed in the statutes variously as irreconcilable differences, incompatibility, or the dissolution of the marital relationship. No proof of wrongdoing is required; the court need only find that the marriage is irretrievably broken and that there is no reasonable prospect of reconciliation. Some states impose a period of separation — typically six months to one year — as evidence of breakdown.
The older fault-based grounds — adultery, cruelty, desertion, habitual drunkenness, and imprisonment — have not been entirely abolished. They remain available in some states as alternative grounds and may still be relevant to financial awards, particularly spousal support, in jurisdictions that permit consideration of marital misconduct. However, the practical importance of fault grounds has diminished substantially in the no-fault era.
Child Custody
The overarching standard in all child custody determinations is the best interest of the child, a standard now codified in some form in every state’s statutes and elaborated through the Uniform Marriage and Divorce Act (1970) and the American Law Institute’s Principles of the Law of Family Dissolution (2002). The best interest standard directs the court to consider a range of factors including the emotional bond between the child and each parent, the parents’ ability to provide for the child’s physical and emotional needs, the stability of each parent’s home environment, the child’s educational and social needs, and, where the child is of sufficient age and maturity, the child’s own preferences.
An essential distinction in American custody law is between physical custody — the child’s actual residence and daily care — and legal custody — the authority to make major decisions concerning the child’s health, education, and religious upbringing. Joint custody, in which both parents share either physical or legal custody or both, has become the preferred arrangement in many states, reflecting a shift from the winner-take-all model of sole custody toward a presumption of continued involvement by both parents.
The tender years doctrine, which once created a presumption in favour of maternal custody for young children, has been largely repudiated. The Supreme Court in Planned Parenthood of Central Missouri v Danforth, 428 US 52 (1976), and state courts thereafter, rejected the doctrine as an impermissible gender-based classification. Modern custody law is formally gender-neutral.
In contested custody cases, the court may appoint a guardian ad litem — typically a lawyer or mental health professional — to represent the child’s interests independently. The Uniform Child Custody Jurisdiction and Enforcement Act (UCCJEA), adopted in every state, provides the jurisdictional framework for interstate custody disputes, establishing the child’s home state as the primary basis for jurisdiction and requiring the enforcement of custody orders across state lines.
Child Support
Both parents have a legal duty to support their children, a duty that survives divorce. The Federal Child Support Enforcement program, established under Title IV-D of the Social Security Act, requires states to adopt child support guidelines as a condition of federal funding. These guidelines create a presumptive child support amount based on a mathematical formula.
The most widely adopted model is the income shares model, used in approximately forty states. Under this model, the court calculates the child support obligation by determining the total income of both parents and applying a statutory percentage representing the average expenditure on children in intact families at that income level. Each parent contributes in proportion to their respective income. The remaining states use a flat percentage of the non-custodial parent’s income.
The duty of support generally continues until the child reaches the age of majority, which is eighteen in most states. Some states extend the duty beyond majority to cover college education expenses, particularly where the parents would have provided such support had the family remained intact. Others limit the duty to age eighteen or to the completion of high school, whichever is later.
Spousal Support
Spousal support, or alimony, is a payment from one former spouse to another following divorce. The modern approach distinguishes among several categories of support. Temporary alimony (also called pendente lite support) is awarded during the pendency of the divorce proceedings to maintain the status quo. Rehabilitative alimony, increasingly favoured, provides support for a limited period to enable the recipient spouse to obtain education or training necessary to become self-supporting. Permanent alimony, reserved in most states for long-term marriages in which one spouse has sacrificed significant career opportunities, continues indefinitely subject to modification upon remarriage, cohabitation, or a substantial change in circumstances.
Courts determine spousal support by reference to a set of statutory factors, which typically include the length of the marriage, the standard of living established during the marriage, the age and health of both parties, the earning capacity of each party, the contributions of each party to the marriage including homemaking and child-rearing contributions, and the financial resources of each party.
Property Division
The division of marital property upon divorce follows one of two distinct legal regimes depending on the state. Nine states — Arizona, California, Idaho, Louisiana, Nevada, New Mexico, Texas, Washington, and Wisconsin — are community property states, together with Puerto Rico. In these states, all property acquired during the marriage is presumptively owned equally by both spouses and is divided equally on divorce. Separate property — property owned before marriage, gifts and inheritances received during marriage, and personal injury awards — belongs to the individual spouse.
The remaining states follow equitable distribution, also known as marital property distribution. Under this model, the court divides marital property between the spouses in a manner that is fair and equitable, though not necessarily equal. The court considers factors including the contributions of each spouse to the acquisition of property, the duration of the marriage, the economic circumstances of each spouse, and the desirability of awarding the family home to the custodial parent.
In both systems, the classification of assets raises complex questions. Retirement assets, including pensions, 401(k) plans, and IRAs, are typically treated as marital property to the extent they were accumulated during the marriage, and are divided through a qualified domestic relations order (QDRO) that permits the distribution of retirement funds without immediate tax consequences. Professional degrees and licences acquired during marriage present a more vexing question; some states treat them as marital property subject to distribution, while others compensate the supporting spouse through an award of rehabilitative alimony calculated to approximate the enhanced earning capacity.
Parentage
The Uniform Parentage Act (UPA), first promulgated in 1973 and revised in 2000, 2002, and 2017, provides a comprehensive framework for the establishment of legal parent-child relationships. The UPA establishes several means by which parentage may be established: a presumption of paternity for a man married to the child’s mother at the time of birth; voluntary acknowledgement of paternity; and adjudication by the court, including through genetic testing.
Following Obergefell, the UPA was revised to provide for the recognition of parentage for same-sex couples. The 2017 Uniform Parentage Act provides that a person married to a woman who gives birth to a child is the child’s legal parent, regardless of the spouse’s sex, and establishes provisions for the recognition of parentage through assisted reproduction and surrogacy arrangements. The Act reflects the broader evolution of American family law toward the recognition of diverse family forms within the constitutional framework established by the Supreme Court.