Obama: I would never have dumped Biden

President Obama said Thursday he would have told campaign aides "there is no way that I'm not running again with Joe BidenJoseph (Joe) Robinette BidenDemocrats will need to explain if they shut government down over illegal immigration Trump thinks he could easily beat Sanders in 2020 match-up: report Biden marks MLK Day: Americans are 'living through a battle for the soul of this nation' MORE" in 2012 — had he been asked.

The president's remarks came on the heels of the book Double Down, in which journalists Mark Halperin and John Heilemann reported that then-White House chief of staff Bill Daley, spooked by the president’s drooping poll numbers in the fall of 2011, ordered campaign staffers to poll and conduct focus groups on the impact of switching Biden for then-Secretary of State Hillary Clinton.

The president, asked in an NBC News interview whether he knew his campaign was researching the idea, said that during his reelection campaign, he was in charge of two million federal employees, as well as a sprawling campaign staff.

"People do all kinds of stuff," Obama said. "Some of it, they clear with me, sometimes they're tryin' to figure somethin' out particularly on the political side. And I'm not somebody who delves into polling and all that data."

But the president said he could "say for certain" that if he had been approached with the idea, he would have shot it down.

"I genuinely believe that he has been one of the best vice presidents in our history," Obama told NBC News. 

"He also happens to be a friend. He also happens to be one of my most important advisers on domestic, foreign policy. I like him. When my back's up against the wall, he has my back."

The president said that he spoke with Biden after the report surfaced and told him that he wouldn't "be here if it weren't for the support that I've had from Joe Biden."

"It's one of the best decisions that I've ever made was selecting him as vice president," Obama added.