The high turnout of Latino and African-American voters for Barack Obama in California had an effect on the vote for a ban on same-sex marriages.

Exit poll data found that seven in 10 black voters and more than 50% of Latino voters backed Proposition 8 on Tuesday.

It will change the California consititution to deny gay and lesbian couples the right to marry, which was confirmed by the state Supreme Court in May.

18,000 couples who got married between June 17th and election day are still legally wed.

With 100% of votes at polling stations counted, 5,424,916 (52.4%) voted in favour of a constitutional definition of marriage being between a man and woman. 4,832,086 (47.6%) voted against. Some postal and absentee votes have yet to be counted.

Black and Latinos make up a third of California’s electorate, and it is thought their Yes votes on Prop 8 were key to its passing.

The Rev Amos Brown of the Third Baptist Church congregation in San Francisco told the Boston Herald:

“I think, to be quite candid, some people feel white gay and lesbian people have not been with them on the issue of race.

“So (African-Americans) said, ’Why should we be concerned about them when they were not concerned about us?’”

Raymond Leon Roker, a black supporter of gay marriage, wrote on the Huffington Post that it is wrong to blame African-Americans.

“It’s an outrage to lay its passage at their feet.

“I’ve read several editorials already about how the ungrateful blacks betrayed gays right after America gave them their first President.

“I know there are some wounds and frayed nerves right now, but this type of condescending, divide and conquer isn’t going to help at all. And it’s a gross oversimplification of what happened.

“According to the exit polling, there’s enough blame to go around. Don’t forget the 49 percent of Asians who voted for Prop 8.

“And the 53 percent of Latinos who fell in line for it too. And then there is the white vote in support of 8.

“Slightly under 50% percent of them, a group representing 63% of California voters, voted “Yes” on 8. Last I checked blacks held little sway over all of those groups.

“Maybe deeper outreach in the black and brown communities could have changed some minds. What about fostering a stronger dialogue beyond the good side of town and in the neighborhoods where some of the unfortunate prejudice takes root?”

Legal challenges to the validity of Prop 8 began even before the votes were all counted.

On Wednesday the American Civil Liberties Union, Lambda Legal and the National Centre for Lesbian Rights filed a writ petition before the California Supreme Court urging the court to invalidate Proposition 8.

The petition charges that Prop 8 is invalid because the initiative process was improperly used in an attempt to undo the constitution’s core commitment to equality for everyone by eliminating a fundamental right from just one group – lesbian and gay Californians.

Proposition 8 also “improperly attempts to prevent the courts from exercising their essential constitutional role of protecting the equal protection rights of minorities.”

According to the California Constitution, such radical changes to the organising principles of state government cannot be made by simple majority vote through the initiative process, but instead must, at a minimum, go through the state legislature first.

“The California Constitution itself sets out two ways to alter the document that sets the most basic rules about how state government works,” the groups said in a statement.

“Through the initiative process, voters can make relatively small changes to the constitution.

“But any measure that would change the underlying principles of the constitution must first be approved by the legislature before being submitted to the voters.

“That didn’t happen with Proposition 8, and that’s why it’s invalid.”