There’s little doubt that Vice President Joe Biden is sorely disappointed that he couldn’t enter the 2016 Democratic presidential campaign, and he seems to be taking out his frustration on former Secretary of State Hillary Rodham Clinton.

Biden made it clear throughout his months-long public agonizing over whether to put himself and his family through another national campaign following the tragic death from cancer of his 46-year-old son, Beau, that he had serious doubts about whether Clinton could either win the nomination or lead their party to victory in November. During an October 21 speech at the White House with his wife, Jill and President Obama, Biden acknowledged that he had run out of time in order to mount a successful presidential campaign.

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Although he didn’t mention Clinton by name, Biden made what some viewed as thinly veiled criticism of her, warning against engaging in excessive partisanship or straying too far from liberal Democratic values on key issues. And last week, while promoting President Obama’s new executive orders on background checks for gun purchases, Biden said to a reporter in Connecticut, that he regrets not seeking the nomination every day but that “it was the right decision for my family and for me.”

Now, as the Democratic primary contests tighten between Clinton and Sen. Bernie Sanders, Biden has poked Clinton in the eye with comments highly sympathetic to Sanders, the self-proclaimed democratic socialist from Vermont who has largely campaigned on the plight of the middle class, income inequality and the excesses of Wall Street.

A new Quinnipiac University poll published Tuesday shows Sanders surging ahead of Clinton in Iowa, with the support of 49 percent of likely Democratic caucus participants to 44 percent for Clinton and four percent for former Maryland governor Martin O’Malley. By comparison, Clinton led Sanders 51 percent to 40 percent in a December 15 Quinnipiac survey.

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The 73-year-old vice president and former senator turned up on CNN Monday evening and staunchly defended Sanders against Clinton’s recent harsh attacks on his record on gun control suggesting that Sanders may be a more authentic champion of liberal causes than Clinton is.

"Bernie is speaking to a yearning that is deep and real. And he has credibility on it," Biden said during an interview with CNN’s Gloria Borger. “And that is the absolute enormous concentration of wealth in a small group of people with the [middle class] being left out.”

When Borger noted that Clinton has also taken strong stands on middle class economic issues and lashed out at Wall Street, Biden replied, "It's relatively new for Hillary to talk about that," while adding that she indeed has "come forward with some really thoughtful approaches to deal with the issue" of income inequality.

"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," the vice president said.

Clinton has stepped up her criticism of Sanders for being soft on gun control. Last Sunday, she hit Sanders again for backing legislation in 2005 while he was a House member that granted manufacturers immunity from legal action in shootings.

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Sanders has frequently said that gun control issues are very complex – especially for lawmakers like him who are from rural pro-gun states like Vermont – but that he would support sensible and effective gun control laws. Biden said that Sanders has sufficiently come around on the issue of gun control to satisfy him.

It’s not clear precisely why Biden is meddling in his party’s presidential race at this point while Obama is trying to keep his distance – unless, of course, he still harbors the fantasy that the Democrats might still turn to him if neither Clinton nor Sanders looks strong enough to carry the day in November general election. While Biden still enjoys some support within his party, polls repeatedly showed that the vice president trailed Clinton and Sanders in hypothetical primary matchups.

Biden told CNN he was not surprised that Sanders was drawing significant support from Democrats, even with his self-identification as a socialist, nor was he surprised that Clinton was struggling in the early caucus and primary states, despite conventional wisdom that she is the prohibitive favorite to secure the presidential nomination.

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"I never thought she was a prohibitive favorite," he said. "I don't think she ever thought she was a prohibitive favorite. So I think it's, you know, everything's sort of coming down to Earth."

And just for good measure, Biden said on NBC’s Today Show this morning that while he hopes Republican frontrunner Donald Trump doesn’t end up as the next president, he concedes that it’s a possibility given the current lineup in the two parties.

"Yes, I think it's possible,'' Biden told Savannah Guthrie during the show’s live broadcast from the White House.

"I hope that if that were to occur — I hope it doesn't because I have fundamentally different views than he does — I'd hope that he gets a lot more serious about the issues, a lot more serious about gaining knowledge about how this nation functions and foreign policy and domestic policy. But look, that's a long way off."