In January 2015, the US Supreme Court granted certiorari in Obergefell v. Hodges, a case from the US Court of Appeals for the Sixth Circuit which upheld state bans on same-sex marriages. The Sixth Circuit's opinion created a circuit split. The US Courts of Appeals for the Fourth, Seventh, Ninth and Tenth Circuits had found state bans on same-sex marriage to be unconstitutional. The US Supreme Court's grant of certiorari in Obergefell marked a departure from its actions in late 2014, where it declined to grant certiorari to other same-sex marriage cases. The court's refusal to grant certiorari resulted in the legalization of same-sex marriage in several states.
The court consolidated four appeals from the Sixth Circuit into Obergefell v. Hodges. The title case, Obergefell v. Hodges, came from Ohio and dealt with widowers seeking recognition from Ohio of the same-sex marriages mentioned on the deceased's death certificates. The widowers succeeded in district court, but the Sixth Circuit reversed the district court and upheld Ohio's ban on the recognition of same-sex marriages.
Another of the cases, Tanco v. Haslam, started in Tennessee and was brought by three couples seeking recognition of their out-of-state same-sex marriages. The Sixth Circuit reversed the district court's ruling in favor of the plaintiffs, and found Tennessee's ban on same-sex marriage to be constitutional. DeBoer v. Snyder is a case where a same-sex couple fought Michigan's ban on adoptions by same-sex couples. Again, this case won at the district court level, and the Sixth Circuit reversed. Bourke v. Beshear is a same-sex marriage case from Kentucky. The district court found that the Equal Protection Clause required the state to recognize same-sex marriages from other jurisdictions, which the Sixth Circuit reversed on appeal.
The petition for writ of certiorari [PDF] in Obergefell features two questions presented, broadly asking whether the Fourteenth Amendment requires a state to license a marriage between two people of the same sex and whether the Fourteenth Amendment requires a state to recognize a marriage between two people of the same sex when their marriage was lawfully licensed and performed out-of-state. In a 5-4 decision decided on June 26, 2015, the Supreme Court answered both [PDF] issues in the affirmative, thereby requiring all states and territories to issue marriage licenses to same-sex couples and to recognize same-sex marriages validly performed in other jurisdictions.