Months before the first ads would run on Proposition 8, San Francisco Catholic Archbishop George Niederauer reached out to a group he knew well, Mormons.

Niederauer had made critical inroads into improving Catholic-Mormon relations while he was Bishop of Salt Lake City for 11 years. And now he asked them for help on Prop. 8, the ballot measure that sought to ban same-sex marriages in California.

The June letter from Niederauer drew in the Church of Jesus Christ of Latter-day Saints and proved to be a critical move in building a multi-religious coalition - the backbone of the fundraising, organizing and voting support for the successful ballot measure. By bringing together Mormons and Catholics, Niederauer would align the two most powerful religious institutions in the Prop. 8 battle.

Ironically, it made San Francisco, center of the nation's gay community, a nexus in the fight against the recently gained gay right to marry.

This Catholic-Mormon alliance was part of a broad pattern that underscored a critical difference between the rival campaigns: Yes on 8 sought to marshal support among many religions, while the No on 8 campaign often put religion on the sidelines.

"People of faith, really of every faith, believed that marriage was between man and a woman," said Frank Schubert, political consultant to the Yes on 8 campaign. "They formed the core of our volunteer operation. They were largely responsible for the 70,000 contributions we got."

Some clergy within the No on 8 campaign believed not enough respect was paid to religion.

"Their focus really wasn't upon communities of faith," said the Rev. Roland Stringfellow, who works with the Center for Gay and Lesbian Studies at the Pacific School of Religion in Berkeley and was an active organizer in the No on 8 campaign. Stringfellow said No on 8's relative neglect of religion had a particularly profound effect on Latinos and African Americans, who hold strong religious views. "I really didn't note particular outreaches to communities of color."

Exit polls data

Exit polls show that religious views had a profound effect on the result, spanning racial lines:

-- 84 percent of those who attend church weekly voted yes.

-- 81 percent of white evangelicals voted yes.

-- 65 percent of white Protestants voted yes.

-- 64 percent of Catholics voted yes. Catholics accounted for 30 percent of all voters.

A late push by many churches to win over their congregations played a decisive role in increasing turnout and swaying opinion, said Mark DiCamillo, director of the Field Poll, who analyzed the figures.

The last Field Poll, conducted a week before the election, showed that weekly churchgoers increased their support in the final week from 72 percent to 84 percent. Catholic support increased from 44 percent to 64 percent - a jump that accounted for 6 percent of the total California electorate and equivalent to the state's entire African American population combined.

The shift in Catholics alone more than accounted for Prop. 8's 5 percent margin of victory.

"The Sunday before the election is just a very influential time for churchgoers," said DiCamillo. For religious conservatives, "there was a lot of interest and attention and concern on this whole issue, but they brought it to a big conclusion on the final weekend."

Stringfellow, who organized No on 8 religious events in the East Bay and San Francisco, said the No on 8 campaign's talking points initially didn't have language to address religious groups. In addition, he said, No on 8 campaigners were told by strategists not to discuss children, an issue that has particular significance for family-oriented religious groups.

Missed opportunities

Stringfellow believes the campaign was afraid it would get smeared by allegations tying homosexuality to pedophilia. But he believes it was wrong to avoid the subject of children because gays and lesbians are just as capable as straight people of being good parents. "When the Yes on 8 folks talked about children, we really didn't have anywhere to go with it," he said.

Stringfellow said the No on 8 campaign was wrong to downplay lesbian, gay, bisexual and transgender couples in advertisements. "It's not going to be normalized if you hide over here in the corner," he said. "There's nothing wrong with talking about love between two individuals."

The future for the religious coalition that supported Prop. 8 is unclear.

"I don't know if it could be assembled again," said Schubert, the Yes on 8 consultant. "It came together because of the unique nature of marriage, and how it carries across every ideological and theological boundary."

Mormon church members undertook a perhaps unprecedented mobilization, contributing an estimated 40 percent of the individual donations made to the Yes on 8's $30 million-plus campaign. Yet the Salt Lake City church, which did not contribute to the campaign, sees its involvement in politics as unusual.

"I don't think there's any sense in the church that this coalition has more life beyond this one issue," said Mike Otterson, a church spokesman. "We haven't created a permanent alliance of churches here. What we did here was we came together to protect traditional marriage."