The first marriages by same-sex couples were celebrated in the United States in May 2004, as a result of the Massachusetts Supreme Judicial Court’s ruling in Goodridge v. Department of Public Health, which held that withholding marriage licenses from those couples ran afoul of the state constitution.
Just eleven years later, the U.S. Supreme Court has ruled in Obergefell v. Hodges that the federal Constitution does not allow any state to prohibit the celebration or recognition of marriages by same-sex couples. In the words of Justice Kennedy, writing for a 5-4 majority and as the author of the third in a trilogy of gay rights cases:
The Constitution . . . does not permit the State to bar same-sex couples from marriage on the same terms as accorded to couples of the opposite sex . . . . [T]he Court also must hold—and it now does hold—that there is no lawful basis for a State to refuse to recognize a lawful same-sex marriage performed in another State on the ground of its same-sex character.
Joanna L. Grossman,
From Zero to Fifty in Eleven Years: The Supreme Court Declares the Right of Same-Sex Couples to Marry in Obergefell v. Hodges Verdict
Available at: https://scholarlycommons.law.hofstra.edu/faculty_scholarship/1008