California state Sen. Scott Wiener and Assemblymember Evan Low recently introduced Assembly Constitutional Amendment 5 (ACA 5) to repeal Proposition 8, the 2008 ballot initiative that banned same-sex marriage in California by adding Article I, Section 7.5 to the state constitution: "Only marriage between a man and a woman is valid or recognized in California."

Proposition 8 was a response to the California Supreme Court decision In re Marriage Cases (2008) 43 Cal.4th 757, which found a state constitutional right to same-sex marriage. Proposition 8 was ultimately abrogated in 2015 by the U.S. Supreme Court, which held in Obergefell v. Hodges (2015) 576 U.S. 644, that the fundamental right to marry under the federal constitution includes same-sex couples. Because of the supremacy clause, the federal constitutional right to same-sex marriage supersedes Proposition 8's state constitutional restriction.