Obama: Democratic election losses are my responsibility

President Obama is borrowing a phrase from predecessor Harry Truman in taking the blame for last week's election losses by Democrats: "The buck stops with me."

"The buck stops right here at my desk," Obama said in an interview with CBS' Face The Nation that aired Sunday. "And so whenever, as the head of the party, it doesn't do well, I've got to take responsibility for it."

While Republicans won control of the Senate and expanded their majority in the House, Obama said the message he took from the elections is that "people want to see this city (of Washington) work."

Obama also offered a succinct analysis of the results: "We got beat."

During the wide-ranging interview with CBS' Bob Schieffer, Obama again vowed to issue new executive orders on immigration — but added that congressional Republicans can override them by passing a comprehensive immigration bill.

"They have the ability, the authority, the control to supersede anything I do through my executive authority by simply carrying out their functions over there," Obama said of Congress.

The minute Republicans pass a bill he can sign, Obama said that "then what I've done goes away."

Republican congressional leaders said they are concerned that Obama's forthcoming executive orders could legalize the status of hundreds of thousands of migrants currently in the country illegally.

Describing that approach as "amnesty," congressional Republicans have also objected to an Obama-backed bill that would provide a pathway to citizenship for people in the country illegally.

Face The Nation, the CBS News program that celebrated its 60th anniversary Sunday, taped the interview with Obama on Friday.

During the session, Obama also:

• Declined to say whether he sent a letter to Iran's supreme leader, but said he is still seeking an agreement on that nation's nuclear program and added that the U.S. and Iran have "a shared enemy" in the Islamic State.

The U.S. and allies are negotiating an agreement in which Iran would forgo the means to make nuclear weapons in exchange for a reduction of sanctions.

The current deadline is Nov. 24, and Obama told CBS that "there's still a big gap. We may not be able to get there."

Obama also said he wants Iranian support for the fight against the Islamic State, also known as ISIL. But he added that "we are not connecting in any way the nuclear negotiations from the issue of ISIL."

• Said his decision to basically double the size of the U.S. force in Iraq — up to around 3,000 troops — signals "a new phase" in the battle against the Islamic State.

While the U.S. maintains airstrikes against ISIL positions in Iraq and Syria, U.S. troops will advise and train local forces to lead the fight on the ground.

"Phase one was getting an Iraqi government that was inclusive and credible, and we now have done that," Obama told CBS. "And so now what we've done is rather than just try to halt ISIL's momentum, we're now in a position to start going on some offense."

• Indicated that changes are coming within the White House staff, not because of a post-election shakeup but rather natural turnover in a sixth-year presidency.

"We will be bringing in new folks here because people get tired, you know," Obama said. "It's a hard job."

He added: "What I've told everybody is, you know, I want you to have as much enthusiasm and energy on the last day of this administration as you do right now or you did when you first started. Otherwise you shouldn't be here."