Proposition 8, known informally as Prop 8, was a California ballot proposition and a state constitutional amendment intended to ban same-sex marriage; it passed in the November 2008 California state elections and was later overturned in court. The proposition was created by opponents of same-sex marriage in advance of the California Supreme Court's May 2008 appeal ruling, In re Marriage Cases, which followed the short-lived 2004 same-sex weddings controversy and found the previous ban on same-sex marriage unconstitutional. Proposition 8 was ultimately ruled unconstitutional by a federal court in 2010, although the court decision did not go into effect until June 26, 2013, following the conclusion of proponents' appeals.

The Supreme Court of California is the highest and final court of appeals in the courts of the U.S. state of California. It is headquartered in San Francisco at the Earl Warren Building, but it regularly holds sessions in Los Angeles and Sacramento. Its decisions are binding on all other California state courts. Since 1850, the court has issued many influential decisions in a variety of areas including torts, property, civil and constitutional rights, and criminal law.