A federal appeals court has ruled that California’s ban on same-sex marriage is unconstitutional, setting up a showdown in the Supreme Court. The state instituted the ban after voters narrowly passed Proposition 8 in 2008. But Tuesday’s panel affirmed by a 2–1 vote that a lower-court judge was correct when he said the referendum violated the U.S. Constitution. Supporters of Proposition 8 had tried to throw out U.S. District Judge Vaughn Walker’s ruling that the ban was unconstitutional on the grounds that he had failed to disclose his sexual orientation. In a separate ruling Tuesday, the appeal court refused to set aside Walker’s decision.