US became 21st Country to Recognize Same-sex Marriage Nationally

Same-sex marriage was completely, nationally legalized in the United States on June 26, 2015 with the landmark decision of Obergefell v. Hodges. The United States became the twenty-first and most populous country to recognize same-sex marriage. The court ruled that the denial of marriage licenses to same-sex couples violates the equal protection clause of the Fourteenth Amendment of the United States Constitution.

Starting in 2003, various lower court decisions, state legislation, and popular referendums had already legalized same-sex marriage to some degree in thirty-seven out of fifty U.S. states, in one U.S. territory, and in the District of Columbia. Federal benefits were previously extended to lawfully married same-sex couples following the Supreme Court's June 2013 decision in United States v. Windsor.

On January 16, 2015, the U.S. Supreme Court agreed to hear four cases, on appeal from the Sixth Circuit, on whether states may constitutionally ban same-sex marriages or refuse to recognize such marriages legally performed in another state. The cases were: Obergefell v. Hodges (Ohio), Tanco v. Haslam (Tennessee), DeBoer v. Snyder (Michigan), and Bourke v. Beshear (Kentucky). They were decided by the court under the heading of Obergefell on June 26, 2015, when a 5:4 majority of justices led by Justice Anthony Kennedy declared there is a constitutional right for same-sex couples to marry and reversed the Sixth Circuit's judgment.