Which country legalized same-sex marriage in 2015 via a Supreme Court decision?

The United States legalized same-sex marriage nationwide in 2015 through the Supreme Court decision Obergefell v. Hodges.

On June 26, 2015, the Supreme Court ruled by a 5–4 vote that the Fourteenth Amendment requires every state to license marriages between same-sex couples and recognize same-sex marriages performed in other jurisdictions. The decision made marriage equality a nationwide constitutional right in the United States.

The case grew out of lawsuits from couples in Ohio, Michigan, Kentucky, and Tennessee. James Obergefell had challenged Ohio's refusal to recognize his marriage to his terminally ill partner, John Arthur, who had married him in Maryland. The Court consolidated Obergefell with related cases from the other states. Justice Anthony Kennedy wrote the majority opinion.

The ruling followed earlier milestones, including Massachusetts becoming the first U.S. state to issue same-sex marriage licenses in 2004 and the Supreme Court's 2013 decision in United States v. Windsor, which struck down part of the Defense of Marriage Act. Canada had already legalized same-sex marriage nationwide in 2005, so it is a common distractor in this question.