The “traditional” definition of marriage historically excluded gay and lesbian couples, leading to a passionate same-sex marriage debate that raged for many decades. As time passed, however, more states bestowed upon same-sex couples the same rights and responsibilities as traditional married couples, while other states explicitly banned same-sex marriage.

This evolution gained considerable speed following the U.S. Supreme Court’s 2013 decision in U.S. v. Windsor, which struck down the clause in the federal Defense of Marriage Act (DOMA) that defined “marriage” and “spouse” as excluding same-sex partners. Ultimately, the U.S. Supreme Court recognized the right of same-sex partners to marry in the 2015 decision, Obergefell v. Hodges.

The following is a summary of same-sex marriage prior to the Obergefell decision, which legalized same-sex marriage nationwide.

Marriage Law Prior to Obergefell and Windsor

In 1996, Congress passed the Defense of Marriage Act (DOMA). Two provisions of DOMA were particularly significant. One allowed states to refuse to recognize same-sex marriages performed under the laws of other states and the other defined “marriage” and “spouse” as being exclusive to opposite-sex partners. This definition controlled over 1,000 federal laws in which marital or spousal status is addressed for purposes of federal benefits.

DOMA didn’t itself ban same-sex marriages, nor did it require states to do so — it only addressed federal marriage benefits and protections. Massachusetts was the first state to legalize same-sex marriage when the state’s Supreme Court ruled on equal protection grounds.

California and Proposition 8

California was the second state to allow same-sex marriage when, in 2008, the California Supreme Court ruled in In re Marriage Cases that the state’s ban on same-sex marriage violated the California constitution’s equal protection clause. However, it wasn’t long after this decision came down that Proposition 8 made it onto the ballot for the November 2008 election.

Prop 8 was written to amend the state constitution to explicitly define a marriage as a legally binding union between a man and a woman.

Prop 8 passed on November 4, 2008 by a slim margin, effectively banning same-sex marriages in California. A vigorous legal battle ensued and a lawsuit was filed by Prop 8 opponents that challenged the validity of the proposition on procedural grounds. Eventually, the California Supreme Court announced that Prop 8 was valid and the state’s constitution was amended, halting same-sex marriages in California.

In 2010, Judge Vaughn Walker ruled that Prop 8 was unconstitutional on the grounds that it violated federal due process and equal protection clauses. The Ninth Circuit affirmed the decision, and it was soon appealed to the nation’s highest court.

In 2013, the U.S. Supreme Court ruled in Hollingsworth v. Perry that private parties lacked standing to defend a state constitutional amendment where the state itself refused to defend it. Therefore, the case was dismissed for lack of standing. This left intact the original district court ruling that Prop 8 was unconstitutional, once again legalization same-sex marriage in California.

Civil Unions

At the time of U.S. v. Windsor, 12 states and the District of Columbia allowed same-sex marriage, either by judicial decision or legislative action. Other states took a different approach. For example, New Jersey didn’t recognize same-sex marriage but did recognize civil unions.

Civil unions offered many of the same rights and responsibilities as a marriage, but only applied if the couple remained within the state that granted the civil union. Other states recognized domestic partnerships, although they varied among the states. Hawaii’s voters affirmed that marriage was only between a man and a woman, but the state had a system of reciprocal benefits in place for same-sex couples.

Significantly, two major issues showed the difficulty with the patch-work system:

  1. How to deal with same-sex marriages that were lawful in the state in which they were performed, but weren’t recognized by other states that didn’t recognize them; and
  2. How to reconcile the law of states that recognized same-sex marriage with the denial of federal benefits under DOMA.

U.S. v. Windsor

The Windsor case involved a New York widow who married her partner in Canada, which was recognized by the State of New York. Her partner died and Ms. Windsor was denied the benefit of a spousal deduction for federal estate taxes because DOMA barred recognition of Ms. Windsor as a “spouse.” She paid more in federal taxes than she would have if the federal government had recognized her marriage.

The U.S. Supreme Court found that the section of DOMA that limited marriage and spouse to only opposite-sex couples was unconstitutional under the Fifth Amendment of the U.S. Constitution. Writing for the court, Justice Kennedy concluded that New York had protected a class of people and DOMA took that protection away, resulting in a violation of basic due process and equal protection.

Because the definition in DOMA applied to a wide variety of federal laws, the holding affected many areas, including Social Security, benefits under the Family & Medical Leave Act (including parental leave), taxes, bankruptcy, immigration, military spousal benefits, to name a few. However, the holding only applied to marriages that were legal under the law of the state.

Obergefell v. Hodges

On June 26, 2015, the U.S. Supreme Court concluded that, under the Fourteenth Amendment to the U.S. Constitution, states must license a marriage between two people of the same sex and must recognize a marriage between two people of the same sex when their marriage was lawfully licensed and performed out-of-State.

In that case, Obergefell v. Hodges, 14 same-sex couples and two men whose same-sex partners were deceased challenged the laws of their states, raising the following two issues:

  1. Whether the Fourteenth Amendment requires a state to license a marriage between two people of the same sex; and
  2. Whether the Fourteenth Amendment requires a state to recognize a same-sex marriage licensed and performed in a state that doesn’t grant that right.

Justice Anthony Kennedy authored a 5-4 decision answering “yes” to both of those questions. After discussing the development of marriage as an institution, and the evolution of the rights of gays and lesbians, the opinion concluded that marriage is a fundamental right that applies with equal force to same-sex couples. Justice Kennedy referenced four principles in reaching this conclusion:

  1. The right to personal choice regarding marriage is inherent in the concept of individual autonomy.
  2. It supports a two-person union unlike any other in its importance to the committed individuals.
  3. It safeguards children and families by providing stability, recognition, and predictability, as well as economic benefits.
  4. Marriage is integral to our country’s social order.

“It is now clear that the challenged laws burden the liberty of same-sex couples, and it must be further acknowledged that they abridge central precepts of equality,” wrote Kennedy. As such, same-sex couples may not be deprived of the fundamental right to marry, meaning same-sex couples may marry in all states, and states must recognize a lawful same-sex marriage performed in another state.