Obergefell v. Hodges, and three cases consolidated with it by the Supreme Court—Tanco v. Haslam, DeBoer v. Snyder, and Bourke v. Beshear—were federal-court challenges to state laws and constitutional amendments adopted by the voters of Ohio, Tennessee, Michigan, and Kentucky that prohibited same-sex couples from marrying and/or forbid the state from recognizing the marriages of same-sex couples lawfully entered into in other states.
https://www.theusconstitution.org/litigation/obergefell-v-hodges-et-al-u-s-sup-ct/