“There will be pressure for the Justice Department to weigh in on the Prop. 8 case,” said Richard Socarides, a longtime gay rights activist and White House adviser to President Bill Clinton.

Socarides said that when Obama “evolved” in the direction of support for gay marriage earlier this year, he and his aides seemed eager to let some time pass before confronting the question of whether it was a right every American should be guaranteed.

“I think this federalizes the issue much more quickly than the White House would have liked and may force them to take a position earlier than they would have liked,” Socarides said.

“It’s a fascinating question,” said another prominent gay rights activist, who asked not to be named. “Will they be at the table and which side of the table will they be at?”