SAN FRANCISCO (AP) – Rep. Barney Frank said San Francisco’s decision to challenge state law and grant marriage licenses to same-sex couples could damage efforts by gay and lesbian rights advocates to defend the Massachusetts court decision legalizing marriage for gays and lesbians.

“I was sorry to see the San Francisco thing go forward,” said Frank, an openly gay congressman from Massachusetts who shared his concerns with fellow Democrat and San Francisco Mayor Gavin Newsom before the city began marrying gay and lesbian couples.

In an interview with The Associated Press, Frank expressed concern that the image of lawlessness and civil disobedience in San Francisco would lead some in Congress to support a federal constitutional amendment banning marriage for gays and lesbians.

Frank said he had hoped Massachusetts’ Supreme Judicial Court decision upholding the right of same-sex couples to marry would serve as a national model for orderly, legal protection of marriage for gays and lesbians.

“If we go forward in Massachusetts and get same-sex marriage on the books, it’s going to be binding and incontestable,” Frank said.

Instead, Frank said, San Francisco’s move promotes the notion that unpopular laws can be broken or ignored.

“When you’re in a real struggle, San Francisco making a symbolic point becomes a diversion,” he said.

California law defines marriage as “a personal relation arising out of a civil contract between a man and a woman.” In addition, voters approved a ballot measure in 2000 that said only marriages between men and women are valid.

Newsom spokesman Peter Ragone praised Frank as a respected leader on gay and lesbian rights issues but denied that the mayor’s decision to issue marriage licenses to gay and lesbian couples promotes illegal behavior.

“We don’t view this as breaking the law,” Ragone said. “We view this as upholding the state’s constitution, which explicitly prohibits any form of discrimination.”