President Barack Obama says there was no way he could avoid urging the Supreme Court to overturn California's ban on gay marriage.

Obama says the nation is going through the same type of evolution he has gone through about gay marriage. He says he's concluded the U.S. can't discriminate against gay couples and he felt it was important to express his views to the court.

He says the California law provides no basis for treating gay couples differently, other than they're not straight.

Obama spoke at a White House news conference the day after his administration on Tuesday filed a friend-of-the-court belief calling on the court to strike down California's Proposition 8 ballot measure.