Reporting from San Francisco -- The California Supreme Court announced Tuesday that it would hear arguments March 5 over the constitutionality of Proposition 8, the November ballot measure that reinstated a ban on same-sex marriage.

The court's decision in the case will come within 90 days of the three-hour hearing, which will be held in San Francisco and broadcast live on the California Channel. In addition to hearing challenges to Proposition 8, the court will consider the fate of 18,000 same-sex marriages that occurred before the November election.

Forty-three groups representing civil rights activists, legal scholars, labor unions, bar associations, state legislators and religious organizations have filed written arguments asking that Proposition 8 be overturned.

Twenty organizations, including religious and legal groups, have argued that the measure should be upheld.

The record number of such briefs filed in a state high court case was 68, and those came in the case that led to the court's historic May 15 ruling in favor of same-sex marriage. Proposition 8 restored the marriage ban.

Gay rights lawyers and the city of San Francisco contend that the ballot measure was an illegal revision of the state Constitution. It is a novel argument that required the attorneys to try to distinguish Proposition 8 from other cases in which the court rejected revision challenges.

California Atty. Gen. Jerry Brown also asked the court to overturn the proposition, but on other grounds. He argued that "inalienable rights" cannot be eliminated without compelling reasons, an argument that, if accepted by the court, would make major new law in California.

UC Berkeley emeritus law professor Stephen Barnett said Tuesday that both challenges were "long shots."

"Brown's is stronger because it has never been tried before, so it's got that going for it, whereas there is a lot of law about what's a constitutional revision," he said. Still, Barnett said he doubted that the moderate, Republican-dominated court would adopt Brown's theory because he said it could have far-reaching consequences.

Even if Proposition 8 is upheld, the court could rule that existing same-sex marriages remain valid. Legal scholars say gay rights lawyers have more ammunition for preserving the marriages than for overturning the ban.

According to final fundraising reports filed this week, both sides in the battle over the ballot measure together raised $83 million -- the most ever for an electoral fight over a social issue in California.

The final tallies for money spent through Dec. 31 show that opponents of the measure raised $44,103,525, while supporters took in $38,766,260.

Supporters of the proposition went to court to ask that no more names and addresses of donors to their campaign be made public because they said some contributors were being harassed and threatened. A federal judge disagreed and made the filings public.

The most recent reports showed that the Church of Jesus Christ of Latter-day Saints donated more than $180,000 in in-kind contributions to the campaign for Proposition 8.

The contributions included tens of thousands of dollars for expenses such as airline tickets, hotels, restaurants and rental cars for top church officials, including L. Whitney Clayton, a church elder.

The church also reported $96,849.31 in contributions consisting of "compensated staff time" for church employees.

maura.dolan@latimes.com