Gay marriage ban vote is expected to be close in Calif.

Five months and thousands of weddings after California's highest court sanctioned same-sex marriage, anxious eyes around the nation will closely follow voters Tuesday as they decide whether to turn back the clock.

Given the state's size and influence, the vote on a constitutional amendment banning gay marriage has become a referendum on sexual orientation and civil rights. Both sides call it the “Gettysburg” of the power struggle between the gay rights movement and the Christian right.

“As California goes, so goes the nation,” Mayor Gavin Newsom boldly predicted the day the state Supreme Court legalized gay marriages.

The race has tightened over the past six weeks and is expected to be close.

Religious and civil rights groups, wealthy philanthropists and middle-class donors have poured $69 million into campaigns for and against Proposition 8, making the initiative the most expensive election question this year outside the race for the White House. Almost $21 million has come from campaign contributors outside California.

Even the presidential candidates weighed in on Proposition 8: John McCain endorsed it, and Barack Obama opposed it. Former President Clinton recorded a telephone message that went to millions of California households Friday asking voters to defeat the measure.

The majority of opinion leaders in the state, including almost every major newspaper, the League of Women Voters, and moderate politicians such as Gov. Arnold Schwarzenegger and Sen. Dianne Feinstein oppose the measure, which critics say unfairly denies one group a basic right.

“This is the most intense and expensive social issues fight we have ever seen. And I think the real reason is because it's very rare in American life (that) we have ever put existing rights on the ballot,” said Patrick Guerriero, a former leader of the gay Log Cabin Republicans who now directs the “No on 8” campaign.

But the measure's opponents have found a formidable foe in the coalition of religious and social conservatives who sponsored the initiative. Since leaders of the Utah-based Church of Jesus Christ of Latter-day Saints appealed to members to back the ban, Mormon dollars and volunteers have streamed into California.

Whitney Clayton, the church's liaison with a coalition called, said the religious right and Mormons see a threat to the fundamental underpinnings of their faiths.

“The impact upon society over the long run is something that makes people very apprehensive,” Clayton said. “What will our children be taught in school? What will happen to the freedom of religion? What will people be able to preach and believe?”

California Roman Catholics, at the urging of bishops, also have stepped up with money and manpower, as have evangelical Christians.

The initiative's backers contend that people of faith will be forced to embrace same-sex marriage if the ban loses, and teachers will be required to inform children about gay relationships, an assertion denounced by education officials.

The measure, which would change the state constitution to limit marriage to a woman and a man, marks the first time voters have been asked to ban same-sex unions retroactively. If passed, it would overrule the state Supreme Court decision in May that said preventing gays from marrying was unlawful discrimination.