The California Supreme Court will issue a ruling at 10 a.m. Tuesday on whether Proposition 8, a constitutional ban on same-sex marriage, will stand.

After three hours of arguments to the court March 5, it seemed as though the seven justices leaned against voiding the measure, but also against voiding the 18,000 same-sex marriages performed last year.

Same-sex marriage advocates argued Proposition 8 — approved by 52.3 percent of voters in November to add to the state constitution a section saying "Only marriage between a man and woman is valid or recognized in California" — was improperly placed on the ballot as an amendment with nothing more than petition signatures. They say it's actually a revision — a sweeping change in the constitution's core principles — which should've required a two-thirds vote of the Legislature or a constitutional convention in order to be placed before voters.

The state of California argued Proposition 8 was an amendment but unconstitutional because it revokes fundamental rights without a compelling government interest.

And same-sex marriage opponents argued the measure should stand as an exercise of Californians' inalienable, sovereign right to amend their constitution as they see fit.

Friday's announcement of the impending ruling touched off a flurry of news releases. Marriage Equality USA spokeswoman Molly McKay said awaiting this ruling "has been an absolutely gut-wrenching experience," as gay and lesbian couples fear not only the faltering economy but the potential stripping away of their rights.

And Courage Campaign Chairman Rick Jacobs said same-sex marriage will prevail no matter how the court rules, as advocates plan to put another ballot measure before voters in 2010 or 2012 seeking to invalidate Proposition 8. "While the tide is turning nationally, restoring marriage equality to California will not be easy. But we know in our hearts that time is on our side, that justice will prevail, and that equality will be ours," he said.