The Supreme Court of the United States ruled on jurisdictional grounds that the Supreme Court of California had the right to overturn the Proposition 8 referendum to amended the State’s which made same sex marriage illegal.
The effect of the ruling is that same sex marriage is legal in California.
Here’s a Plain English take on Hollingsworth v. Perry, the challenge to the constitutionality of California’s Proposition 8, which bans same-sex marriage: After the two same-sex couples filed their challenge to Proposition 8 in federal court in California, the California government officials who would normally have defended the law in court, declined to do so. So the proponents of Proposition 8 stepped in to defend the law, and the California Supreme Court (in response to a request by the lower court) ruled that they could do so under state law. But today the Supreme Court held that the proponents do not have the legal right to defend the law in court. As a result, it held, the decision by the U.S. Court of Appeals for the Ninth Circuit, the intermediate appellate court, has no legal force, and it sent the case back to that court with instructions for it to dismiss the case