Obama's news conference: fiscal cliff, Petraeus, Libya

• Obama insisted that he was committed to keeping his promise to raise taxes on the wealthiest Americans
• He blistered two Republican senators who criticized United Nations Ambassador Susan Rice
• He hopes for a partisan deal on immigration

WASHINGTON — President Obama set a defiant tone Wednesday in his first news conference since he was re-elected, refusing to back down on taxes, defending his U.N. ambassador against GOP attacks and declining to criticize the FBI's handling of the investigation of his CIA director.

Obama insisted that he was committed to keeping his promise to raise taxes on the wealthiest Americans, setting him at loggerheads with GOP lawmakers who say they are unwilling to consider raising taxes as the two sides ramp up negotiations on avoiding the looming "fiscal cliff."

He blistered two Republican senators who criticized United Nations Ambassador Susan Rice for her explanation of the attack Sept. 11 in Benghazi, Libya, that left four Americans dead. "If Sen. (John) McCain and Sen. (Lindsey) Graham and others want to go after somebody," he said, "they should go after me. ... To besmirch her reputation is outrageous."

The president answered questions on topics ranging from his hopes for a partisan deal on immigration to his plan to collaborate on some issues with GOP presidential challenger Mitt Romney.

Obama said a central facet of his successful re-election pitch to voters was a promise that the wealthiest Americans would see George W. Bush-era tax cuts expire at the end of this year.

"I think every voter out there understood that that was an important debate, and the majority of voters agreed with me," he said.

He said he was "not going to slam the door" on Republicans if they offered alternatives to raising revenue to staunch the nation's deficit problem. But he underscored his and his advisers' long-standing opinion that it would be difficult to make up the revenue that would be lost if the Bush tax cuts were extended for America's top earners.

Obama said ending the tax cuts for the wealthiest, while making sure that middle-class taxes don't rise, would mark a giant step toward avoiding the fiscal cliff and the more than $600 billion in automatic budget cuts and tax hikes that come with it.

"We should not hold the middle class hostage while we debate tax cuts for the wealthy," he said.

Rep. Dave Camp, R-Mich., the chairman of the House Ways and Means Committee, said Obama was wasting time with a plan that is a non-starter with Republicans.

"Time is running short, and, frankly, we don't have time to waste on offers that are going nowhere," Camp said. "Raising taxes will not create jobs. Tax reform, however, will not only create jobs but it can produce more revenues – something the president wants. I urge the president to begin serious and substantive negotiations with Congress. We are ready."

Obama reflected on the responsibility he said Americans gave him by electing him to a second term. But he quipped that he had read all the literature on presidential overreach in second terms.

"I've got one mandate," Obama said. "I've got a mandate to help middle-class families and families that are working hard to try to get into the middle class. That's my mandate. That's what the American people said. They said, 'Work really hard to help us.'"

In other matters, Obama said he was "withholding judgment" on the manner in which the White House was notified about the FBI's investigation of CIA Director David Petraeus, who resigned after admitting to an extramarital affair. The investigation began in the summer, but the White House did not learn about it until Election Day.

"It is also possible that had we been told, then you'd be sitting here asking a question about why were you interfering in a criminal investigation," Obama said. "So I think it's best right now for us to just see how this whole process unfolded."

Obama said he expects to see a comprehensive immigration bill introduced in Congress "very soon" after his inauguration in late January. The White House staff has begun conversations with members of the Senate and the House on the issue, he said, and he suggested Latinos' strong showing at the polls last week has hastened lawmakers efforts to tackle the issue.

"I'm very confident that we can get immigration reform done," Obama said.