California voters passed Proposition 8, a ballot initiative that defined marriage as between a man and a woman and effectively banned same-sex couples from marrying.

The passage of Proposition 8 was a major setback for same-sex marriage advocates, who had won a series of legal victories in the years leading up to the vote.

In 2008, the California Supreme Court ruled that same-sex couples had the right to marry under the state constitution. This decision was overturned by Proposition 8, which was passed by a narrow margin of 52% to 48%.

The passage of Proposition 8 was a major disappointment for same-sex marriage advocates, who had hoped that California would become the first state to legalize same-sex marriage through a popular vote.

However, the passage of Proposition 8 also galvanized same-sex marriage advocates, who redoubled their efforts to overturn the ban. In 2013, the U.S. Supreme Court struck down Section 3 of the Defense of Marriage Act (DOMA), which had defined marriage as between a man and a woman for the purposes of federal law. This decision paved the way for the legalization of same-sex marriage in California and other states.

In 2015, the U.S. Supreme Court ruled in Obergefell v. Hodges that same-sex couples have the right to marry under the U.S. Constitution. This decision effectively overturned Proposition 8 and legalized same-sex marriage throughout the United States.