Many prominent Democrats have reacted skeptically to renewed reports that Vice President Joe Biden may yet jump into the 2016 presidential race, even those party activists who are wary of Hillary Clinton and had urged Massachusetts Sen. Elizabeth Warren to challenge the Democratic front-runner.

“There is not much difference between Clinton, Obama and Biden. None of them are willing to challenge the bankers and Wall Street promoters of austerity,” said Roger Hickey, co-director of the Campaign for America’s Future, a liberal group that has argued Clinton is too centrist.

In an interview on CNN Sunday, Van Jones, a progressive activist and former senior Obama administration aide, said of Biden, “there’s no hunger for him.”

“He is incredibly respected. He's a beloved figure in our party. But the reality is he's not so different from Hillary Clinton, from the point of view of the rising energy in the party,” added Jones. “The new party, the Elizabeth Warren wing, Bernie Sanders, Black Lives Matter … they want authenticity. So, he checks the authenticity box, but no other box in our party."

Jones, like Hickey, has been a skeptic of Clinton’s candidacy.

Neil Sroka, a spokesman for the liberal group Democracy for America, which had been urging Warren to run, was also non-committal on Biden’s candidacy.

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“Should he decide to run, we’ll be looking forward to hearing more about Vice President Biden’s vision for the future of our country, and in particular, how he plans to address our nation’s income inequality crisis,” said Sroka.

He added, “a strong primary with a number of seasoned challengers, including Vice President Biden, will only leave the Democratic Party stronger.”

Since a New York Times report on Saturday suggested Biden was seriously mulling a run, there has been much speculation about the vice-president challenging Clinton. Josh Alcorn, a senior adviser to Joe Biden's late son Beau, is joining the Draft Biden Super PAC to lay the financial groundwork for a potential presidential bid.

But there are few signs of a groundswell in the party to urge Biden to run. And some party officials who like Biden and worked with him in the past warned he had waited too late to challenge Clinton. Interviewed on NBC's "Today," former senior Obama adviser David Axelrod, asked if he would advise Biden to enter the race, said, "I would not."

Former Pennsylvania Gov. Ed Rendell, in an interview on MSNBC, said Biden would be a "formidable" candidate, but added, "it's late to start making a campaign."

“Late entrants into presidential campaigns have typically not fared well. Think Wes Clark and Fred Thompson,” said one Democrat who was an aide on Obama’s 2008 and 2012 campaigns. “Your numbers are always higher before you get into the race. Just ask Secretary Clinton. Electeds [elected officials) and donors are tied up, and organizers [for Clinton and other candidates] are on the ground.”

Another veteran party strategist, who did not want to be quoted criticizing Biden, said, “Clinton has more than ample support to win the party's nomination, but Joe Biden will bring candor and grace to the Democratic debates.”

If he opted to challenge Clinton, it’s not clear where Biden would find a political base. Vermont Sen. Bernie Sanders has for now grabbed the backing of liberal activists who are looking for a progressive alternative to Clinton and had been urging Warren to enter.

Biden may be ill-positioned to win those voters, having been a key part of the Obama administration, which many of the activists feel has been insufficiently liberal and avoiding policies like breaking up big Wall Street banks and creating a Medicare-for-all health care program.

Biden is popular among African-Americans, but so is Clinton, so it’s not clear he can make black voters the base of his candidacy. And the party’s establishment, particularly major donors and elected officials, have already bypassed Biden to embrace Clinton, and there is no sign yet they are ready to abandon her.

“Of course not,” said Robert Zimmerman, a longtime Democratic National Committee member and party fundraiser, when asked if he consider changing his support from Clinton to Biden.

“Joe Biden has every right and Joe Biden by every measure should consider running for president. He has served the country honorably and very well as a senator and vice president,” said Zimmerman. “But my support for Hillary Clinton and the support that she has on the grassroots level is a very deep, personal commitment.”