A federal judge in San Francisco is scheduled to rule today on whether Proposition 8, California's voter-approved ban on same-sex marriage, violates the U.S. Constitution.
The case before U.S. District Judge Vaughn Walker has been the nation's first federal trial on a U.S. constitutional challenge to a state law prohibiting gay marriage.
A previous five-year battle over same-sex marriage in California centered on the state rather than federal constitution.
The federal trial pits two same-sex couples who want to marry against the sponsors of Proposition 8 and their campaign committee, ProtectMarriage.com.
The measure was enacted as a state constitutional amendment by California voters in 2008 and provides that "only marriage between a man and a woman is valid or recognized in California."
Walker heard evidence in the nonjury trial in January, presided over closing arguments in June and, according to a court spokeswoman, will file a decision between 1 p.m. and 3 p.m. today.
Both sides have said Walker's court is only the first stop and that they will appeal if they lose, first to a federal appeals court in San Francisco and then likely to the U.S. Supreme Court.
In fact Proposition 8's sponsors filed a motion late Tuesday asking him to stay his ruling if he decides to strike down the ban while they appeal to the 9th U.S. Circuit Court of Appeals.
Proposition 8 attorney Charles Cooper argued in the filing that the sponsors are likely to win on appeal and that allowing same-sex marriage in the interim would cause confusion and uncertainty.
Cooper wrote, "Another purported window of same-sex marriage in California would cause irreparable harm."
The last window of same-sex marriage in the state occurred between June 2008, when a California Supreme Court ruling allowing gay weddings under the state Constitution went into effect, and Nov. 4, 2008, when voters approved Proposition 8.
About 18,000 same-sex couples married during that time, and the state high court left those marriages in place at the same time that it upheld voters' right to enact Proposition 8 in a decision in May 2009.