U.S. state constitutional amendments banning same-sex unions

Prior to the Supreme Court's decision in Obergefell v. Hodges (2015), U.S. state constitutional amendments banning same-sex unions of several different types passed, banning legal recognition of same-sex unions in U.S. state constitutions, referred to by proponents as "defense of marriage amendments" or "marriage protection amendments."^[1] These state amendments are different from the proposed Federal Marriage Amendment, which would ban same-sex marriage in every U.S. state, and Section 2 of the Defense of Marriage Act, more commonly known as DOMA, which allowed the states not to recognize same-sex marriages from other states. The amendments define marriage as a union between one man and one woman and prevent civil unions or same-sex marriages from being legalized, though some of the amendments bar only the latter. The Obergefell decision in June 2015 invalidated these state constitutional amendments insofar as they prevented same-sex couples from marrying, even though the actual text of these amendments remain written into the state constitutions.

Thirty-one U.S. state constitutional amendments banning legal recognition of same-sex unions have been adopted. Of these, ten make only same-sex marriage unconstitutional; sixteen make both same-sex marriage and civil unions unconstitutional; two make same-sex marriage, civil unions, and other contracts unconstitutional; and one is unique. Hawaii's amendment is unique in that it does not make same-sex marriage unconstitutional; rather, it allows the state to limit marriage to opposite-sex couples. Virginia's amendment prevents the state from recognizing private contracts that "approximate" marriage. Observers have pointed out that such language encompasses private contracts and medical directives.^[2][3] Furthermore, the Michigan Supreme Court has held that the state's amendment bans not only same-sex marriage and civil unions, but also domestic partnership benefits such as health insurance.^[4] On November 3, 2020, Nevada became the first U.S. state to repeal its amendment banning same-sex marriage following approval of 2020 Nevada Question 2.

State constitutional amendments are typically approved first by the legislature or special constitutional convention and then by the voters in a referendum.^[a] In some states, one or both of these steps is repeated.^[b] The percentages shown in the list are results from the referendum stage, not the legislative stage.

Cite error: There are <ref group=lower-alpha> tags or {{efn}} templates on this page, but the references will not show without a {{reflist|group=lower-alpha}} template or {{notelist}} template (see the help page).