As the California Supreme Court takes up the issue of same-sex marriage today, evangelical leaders from across the country are preparing for a fight some of them say is a battle for Western Civilization itself.

The court’s seven justices will hear two hours of arguments in their San Francisco courtroom on whether San Francisco Mayor Gavin Newsom and other officials had the authority to defy state laws that define marriage as being between a man and a woman.

City officials issued about 4,000 same-sex marriage licenses between Feb. 12 and March 11, when the state’s high court ordered a halt.

The court will be considering only one narrow issue in the dispute over whether same-sex marriages should be allowed in California.

That issue is whether the San Francisco officials had the right to decide on their own, without the backing of an appellate court ruling, that the state marriage laws are unconstitutional.

Meanwhile, the broader constitutional issue is separately working its way slowly through state trial courts. At least six lawsuits arguing for or against the right of homosexuals and lesbians to marry are now pending in San Francisco and Los Angeles superior courts. But it could take two or three years for those cases to reach the state’s highest court.

The California Supreme Court justices will be looking at two lawsuits filed by California Attorney General Bill Lockyer and by three San Francisco citizens represented by the Arizona-based Alliance Defense Fund, a conservative family-values group.

Meanwhile, over the weekend, pro-family leaders called on Christians to get involved in the debate over same-sex “marriage” by pushing for the passage of the Federal Marriage Amendment.

“I am not exaggerating when I say the next 12 to 18 months will likely determine not only the future of this country, but of Western Civilization,” Family Research Council President Tony Perkins said.

Perkins and other pro-family leaders spoke to some 500 churches and 1,500 radio stations via satellite and the Internet at an event titled the “Battle for Marriage.” The simulcast took place six days after Massachusetts became the first state to legalize same-sex “marriage.”

“This is such a critical moment,” Focus on the Family founder James Dobson said. “We do stand at a crossroads.”

Dobson said events of recent weeks – including the fact that Congress seems indifferent to the issue – have made him “discouraged.”

“It just seems like … a mountain too high to climb,” Dobson said. “And I have been chastised by the Lord for that [attitude]. He is still on the throne.”

Chuck Colson, founder of Prison Fellowship, called the fight over same-sex marriage, “the mother of all culture war battles. This is the one that decides what kind of a country we’re going to be.”

Traditional marriage, Dobson said, cannot “co-exist with homosexual ‘marriage.’ It will destroy the family.”

Colson called evangelical Christians “the great sleeping army” and said they are the key to forcing congressional support for a federal marriage amendment.

Dobson added that same-sex marriage is a threat to families and religious freedom and could mean “the end of morality.”

“I’m now the new arch-homophobe,” Dobson said. “I’ve been called a lot of names. That’s a new one.”

Related stories:

U.S. Supreme Court won’t block same-sex marriage

Judge won’t stop same-sex marriage

Suit filed to stop same-sex marriage

9 days to same-sex marriage

Bill seeks ouster of Massachusetts justices

Federal Marriage Amendment dead?

How homosexual activists took America by surprise

California high court blocks S.F. ‘marriages’

Bush announces support for marriage amendment

Activists respond to Bush amendment stance

Marriage defenders slow same-sex tide

Mayor facing charges for same-sex weddings

Another city backs same-sex marriage

Same-sex marriage comes to N.Y. town

Action filed to remove S.F. mayor, AG

Note: Read our discussion guidelines before commenting.