Biden tells Colbert 'I'd be lying if I said that I knew I was there' when asked about presidential run

Vice President Joe Biden, in an emotional interview with comedian Stephen Colbert on Thursday, said he was not in a place to say that he could devote his full self to running for president again.

Biden told the host of CBS's "The Late Show" that anyone running for the White House should be able to tell Americans that his or her whole heart, soul, energy, and passion were in the race.

"I'd be lying if I said that I knew I was there," Biden, whose son Beau died recently, said in the interview.

"Nobody has a right, in my view, to seek that office unless they're willing to give it 110 percent of who they are. And I am, as I said, I'm optimistic, I'm positive about where we're going," Biden told Colbert, according to the Associated Press. "But I find myself - you understand it - sometimes it just overwhelms you."

Colbert urged the vice president to run.

Biden has been considering stepping into the race to challenge Secretary of State Hillary Clinton for the 2016 Democratic presidential nomination, but as the AP noted, the interview with Colbert suggested he was leaning against running in light of his son's recent death from brain cancer.

During the interview with Colbert, Biden recalled breaking down while he was on a military base and somebody good-naturedly yelled out his son's name, according to the AP.

"All of the sudden," Biden said, "I lost it."

(Reuters Reporting by Jeff Mason; Editing by Sandra Maler)