The California Supreme Court will rule today on whether Proposition 8 -- the state's controversial ban on gay marriage that was passed by ballot referendum last November -- is valid.
The ruling will also determine the status of about 18,000 same-sex couples who married before the constitutional amendment was passed by 52 percent of the vote. The contentious $83 million campaign pitted gay rights activists against Christian church groups including the Mormons.
Justices are considering a series of lawsuits that seek to overturn the ban, which overruled a 4-3 court decision that briefly legalized same-sex marriage. Those suits claim Proposition 8 was put on the ballot improperly.
Gay rights marches -- either celebratory or in protest -- have been scheduled throughout California and several other states tonight, depending on which way the high court swings.
Waiting for the decision "has been an absolutely gut-wrenching experience," Molly McKay, a spokeswoman for Marriage Equality USA, told the Associated Press.
"As Californians, we are all under tremendous strain worrying about the economy, our jobs and our families," she said. "On top of that, gay families have been living for months with the fear that the court will allow a bare majority of voters to strip gay and lesbian families of their constitutional protections and eliminate our marriages -- or just as bad, eliminate new couples' ability to get married."
Opponents of Proposition 8 argued that it revised the California's equal protection clause to such a dramatic degree that its sponsors needed the Legislature's approval to submit it to voters.
But several justices at a March hearing said they were skeptical of that argument and many legal experts say the Supreme Court would not likely undermine the state's citizen initiative process by reversing the gay marriage ban.
Since the passage of Proposition 8, gay marriage has gained momentum around the nation. Iowa, Maine and Vermont have joined Massachusetts and Connecticut in recognizing same-sex couples. Similar proposals are under way in New Hampshire and New York.
If California's court upholds the gay marriage ban, gay rights advocates hope to have it repealed in a 2012 ballot initiative. Groups have already begun raising money and airing television ads.
If the justices strike down the lawsuits, Proposition 8 supporters could ask for a legislative proposal to limit marriage to between a man and a woman.
The Democratic-controlled California Legislature has twice passed measures to legalize gay marriage, but they were vetoed by Gov. Arnold Schwarzenegger.
With passage of Proposition 8, California amended its constitution to specify that only marriage between a man and a woman is valid or recognized.
In June 2008, the state's Supreme Court overturned a gay marriage initiative. That decision allowed thousands of gays and lesbians to be legally married in that state; gay couples across the state decided not to take their chances, choosing to marry before voters took up the measure.
The passage of Proposition 8 set off a backlash that rippled across state borders. Organizers used Internet sites such as Facebook to draw huge crowds from New York to Los Angeles and cities in between.
Advocates turned the vote on Proposition 8 into a countrywide referendum on gay rights, calling it "the new frontier in the civil rights movement."