Vice President Joe Biden described Bernie Sanders on Monday as more authentic on economic inequality than Hillary Clinton and defended Sanders' record on gun control. Weighing in on the Democratic race he almost joined, Biden said he never felt Clinton was the prohibitive favourite to win.

In an interview with CNN, Biden also disclosed that President Barack Obama offered him money when his son's health declined and made him promise not to sell his house. Beau Biden died from brain cancer last May.

Biden, who decided not to run months after his son's death, said Sanders speaks to "a yearning that is deep and real" on issues of wealth disparity and people left out of the economy. He said Sanders had credibility on the issue, but that for Clinton, the issue was relatively new.

"Hillary's focus has been other things up to now, and that's been Bernie's — no one questions Bernie's authenticity on those issues," Biden said. He went on to say people question anybody who hasn't been talking about the issue that long.

He also said Clinton, who has coalesced much of the Democratic establishment's support, had a high bar to meet as the perceived favourite to win her party's nomination.

"I never thought she was a prohibitive favourite. I don't think she ever thought she was a prohibitive favourite," said Biden, who praised Clinton at other points in the interview.


Democratic presidential candidates Hillary Clinton, right, and Sen. Bernie Sanders, I-Vt., are shown in October during the second candidates debate. (John Locher/Associated Press)

Biden's remarks offered some of the first public insight into his machinations about the 2016 race and particularly the Democratic field. Biden and Obama have not endorsed, and Obama's chief of staff has said the president won't take sides in the primary. Biden's endorsement would be highly coveted by any of the Democratic candidates.

But a campaign dispute erupted last week between Sanders and Clinton after Obama, aiming to ramp up political pressure on gun control, said he wouldn't endorse or campaign for any candidate who opposes what he described as common sense gun control, and he mentioned liability for gun-makers as a key issue. White House officials later noted that Sanders has said he's open to revisiting the liability issue.

"Bernie Sanders has said that he thought the president's approach is the correct approach. Bernie Sanders said that he thinks there should be liability now," Biden said. Asked whether Sanders needed to change his position to qualify for his support, Biden said no.

In the interview, Biden also revealed an offer Obama made during lunch as Biden's son, the former Delaware attorney general, was losing his ability to speak. Concerned about how his son's family would support themselves without his salary, Biden said he and his wife had discussed selling their house.

"He said, 'I'll give you the money,"' Biden recalled referring to Obama. "Whatever you need, I'll give you the money. Don't, Joe — promise me. Promise me."