Vice President Joseph R. Biden Jr. apologized to President Obama for hastening him into an endorsement of same-sex marriage, several people briefed on the exchange said Thursday, even as the White House sought to capitalize in the campaign on Mr. Obama's long-awaited expression of support.

In an Oval Office meeting with Mr. Obama on Wednesday, hours before the president confirmed his own support, Mr. Biden expressed regret for a statement endorsing same-sex marriage that went considerably further than the president's views on the matter and scrambled the White House's calculation for confronting the charged social issue.

As the president traveled to the West Coast on Thursday, where in Seattle he said Americans should have the chance to succeed ''no matter who you love,'' his presumptive challenger, Mitt Romney, and Republican leaders in Congress, tried, with limited success, to steer the focus of the presidential campaign back to the nation's sluggish economy.

When Mr. Romney addressed hundreds of donors and other supporters at a pair of campaign stops in Nebraska, one of the nation's most reliable Republican states, he steered clear of the topic of same-sex marriage, underscoring Republican caution over the shifting politics of the gay marriage debate. On Capitol Hill, Speaker John A. Boehner deflected questions about same-sex marriage, declaring: ''The president can talk about it all he wants. I'm going to stay focused on what the American people want us to focus on, and that's jobs.''

