Even as African-American and Latino voters were a powerful force in boosting America's first black president to victory, in California they also were crucial to passing Proposition 8, a ballot measure labeled, "Eliminates right of same-sex couples to marry."

Exit polls showed that 70 percent of black voters, and a majority of Latino voters, voted yes on Proposition 8, one likely reason why the measure won a slim majority in Los Angeles County, where pre-election polls had suggested it would lose, even though it lost by a huge margin in the Bay Area.

The Rev. Amos Brown might have foreseen Proposition 8's victory. As Brown preached Sunday to his congregation that they should be mindful of everyone's civil rights when they voted on same-sex marriage this week, a church member tried to wrestle away the microphone, agitated that the preacher was discussing gay marriage in the black church.

Gloria Nieto had a sense of those demographic forces, too. When Nieto, a lead organizer for the No on Proposition 8 campaign in San Jose, wanted to distribute campaign signs in Spanish and Vietnamese this fall, she had to get them made herself because the statewide campaign only had signs in English.

Those may have been two hints that Proposition 8 was headed for Tuesday's clear 5-point victory. The measure was one of the most popular on Tuesday's ballot, its 5.4 million yes votes helped — not hindered, as many had predicted — by the large turnout to vote for Barack Obama.

Wednesday was a day of rejoicing for the supporters of Proposition 8, a day of worry for the estimated 18,000 same-sex couples who married between June 16 and Election Day — and a day of legal threats to get those marriages nullified or the new constitutional ban thrown out.

But it was also a day to ponder how the major statewide polls had been so wrong to suggest that a big Obama win would doom Proposition 8.

"To be honest with you, we were kind of fearing that a great outcome for Obama would mean a defeat on Proposition 8, but we found out that African-American people, they are very conservative," said the Rev. Nestor Morales, a San Jose pastor who helped organize Bay Area churches to raise money for Yes on 8 ads in Spanish. "We found a lot of Democrats voting for Obama and voting yes for Proposition 8. Even Latinos, a lot of Latinos that voted for Obama, they also voted yes on Proposition 8."

Proposition 8: Before and during the vote, reaction after the measure passed

In San Francisco, Mayor Gavin Newsom, appearing at times exasperated and calling forth images of the civil rights movement, told reporters that the ban had set back California morally, legally and economically.

"Who would have thought in our lifetime we would have an African-American president?" Newsom said. "I never would have thought in my life I would see a constitution changed to take rights away."

Newsom declined to speculate whether Proposition 8's victory would hurt his bid for governor in 2010, but said he did not regret his advocacy. "I have tremendous faith and confidence about the future of this effort," he said. "People want to be treated to same. I'll keep fighting for 'em."

Just Tuesday, Alice Huffman, president of the California State Conference of the National Association for the Advancement of Colored People, sent a memo to reporters forecasting that a large minority turnout would help to defeat Proposition 8. Huffman was not available for comment Wednesday.

Brown said that he had preached to his Third Baptist Church congregation in San Francisco that African-Americans especially should remember the connection between the Bible's Golden Rule — "Do unto others as you would have others do unto you" — and equal protection under the Constitution. However, he noted, some people didn't see gay marriage as their issue.

"I think, to be quite candid, some people feel white gay and lesbian people have not been with them on the issue of race," he said. "So (African-Americans) said, 'Why should we be concerned about them when they were not concerned about us?' "

Oscar Dace, senior pastor of the Bible Way Christian Center in San Jose, said it may have rankled some African-Americans to hear civil rights for gay and lesbian people compared to the civil rights struggles of blacks in the 20th century.

"Many African-Americans are very conservative when it comes to moral social issues. When it comes to the policy issues they are somewhat liberal. They could see Barack Obama on one hand and see the conservative, evangelical understanding on the other hand," he said.

Nieto, who is Latina, faulted the No on 8 campaign for not working hard enough to build ties to minority voters.

"The LGBT community has not done a good job of having relations with people outside of a white middle-class group," said Nieto. Among the leadership of the No on 8 campaign, "I could not find any evidence of any African-Americans or Latinos that were on the steering group. Even if it was one or two, that's not good representation."

It particularly rankled Nieto that the No on 8 television ads showed very few gay or lesbian people — an omission also noted by other critics.

"We had no identity; we had no names," Nieto said. "We were just this group of people that the Mormons were painting as asking for special rights and trying to make their children be taught about gay marriage in the first grade."

Many in San Francisco, however, were less than distraught about Tuesday's historic exercise of democracy.

Esteban Guevara, a gay man, stood by a "No on Prop. 8" sign made from miniature decorative pumpkins, lichen and tree branches in a store window.

"It's sad, but we got what we really needed — we got a much better president," he said. "And this is just fuel. This won't stop the gay rights movement at all."

Contact Mike Swift at (408) 271-3648 or at mswift@mercurynews.com.

PROP. 8
Yes: 52.5 percent
No: 47.5 percent