The California Supreme Court may decide today whether it is to review a challenge to Proposition 8 – the Constitutional amendment that forbids gay marriage in the state – or dismiss it.

The highest court has been under intense pressure to act from all sides, with gay marriage ban backers threatening to oust any justice that votes in favor of invalidating the Constitutional amendment and gay activists protesting in the streets.

Gay activists began marching and protesting the day after California voters approved the gay marriage ban two weeks ago. On Saturday, over 300 cities participated in a coast-to-coast protest. Organizers say 100,000 people showed up at city halls and public venues to express their disapproval of the California Constitutional amendment, as well as similar measures passed in Florida and Arizona.

Proponents of the gay marriage ban have already threatened to work to oust any justice who votes to invalidate Proposition 8. And they have already begun targeting politicians who support gay marriage, Senator Dianne Feinstein and Governor Arnold Schwarzenegger included.

Tony Perkins of the Family Research Council said last week that the governor was advocating “anarchy” because he supported efforts to invalidate the Constitutional amendment. Forty-four Democratic legislators have signed a friend of the court brief in support of the challenge.

The six lawsuits filed by a coalition of pro-gay rights groups, churches and local governments claim Prop. 8 is invalid becaue it alters the Constitution's “core commitment to equality for everyone by eliminating a fundamental right from just one group, lesbian and gay Californians.”

“If the voters approved an initiative that took the right to free speech away from women, but not from men, everyone would agree that such a measure conflicts with the basic ideals of equality enshrined in our Constitution,” Jenny Pizer, a staff attorney with Lambda Legal, said in a statement announcing the challenge.

The pro-gay rights groups say the gay marriage ban used an improper vehicle – a voter ballot – to alter the Constitution. They contend that such a measure is only valid when making superficial changes to the Constitution. To change the underlying principles of the Constitution, a measure must first be approved by the Legislature before being submitted to the voters on a ballot. Proposition 8 radically alters the California Constitution by removing rights previously given by the Constitution itself, and relied on the voter ballot to accomplish its goal, rights groups say.

“A major purpose of the Constitution is to protect minorities from majorities,” said Elizabeth Gill, a staff attorney with the ACLU of Northern California. “Because changing that principle is a fundamental change to the organizing principles of the Constitution itself, only the legislature can initiate such revisions to the Constitution.”

A decision for review of the lawsuits is not an endorsement of gay marriage. In fact, most scholars agree the challenge is a longshot.

“It's very hard to argue that this narrowly written Constitutional amendment changes the fundamentals of our state government,” Ethan Leib, a Constitutional law professor at UC Hastings in San Francisco, told SFGate.com.

Leib, who is a supporter of gay marriage, called California's Constitutional amendment procedure “flexible and inviting,” because “the people, rather than the judges, get to say what the Constitution means.”