"This last election cycle, we've seen a whole new level of energy that has emerged through a lot of fresh faces, and the party has moved in that direction and wants to hear new ideas and different messages," said Norm Sterzenbach, a former executive director of the Iowa Democratic Party who now works as a consultant in the state.
Added Jim Manley, longtime Democratic operative: "I'm not convinced Biden is the right way to go at this point in time."
"The folks I've talked to are a little taken aback" by his potential candidacy, Manley said. "No one quite understands where it's coming from."
McClatchy interviewed 31 Democratic strategists - pollsters, opposition research experts, media consultants, ex-party officials and communications specialists - from across the country about a potential Biden campaign. Nine agreed to speak on the record; all others quoted anonymously do not plan to be affiliated with any candidate running in the presidential primary.
Strikingly, these conversations yielded a similar view: The Democratic political community is more broadly and deeply pessimistic about Biden's potential candidacy than is commonly known. While these strategists said they respect Biden, they cited significant disadvantages for his campaign - from the increasingly liberal and non-white Democratic electorate to policy baggage from his years in the Senate and a field of rivals that includes new, fresh-faced candidates.
"Among political professionals, there are deep concerns because we know the history," said a Pennsylvania-based Democratic strategist, granted anonymity to speak candidly about a party elder. "We have reason to be skeptical of the hype."
"We heard it with Hillary, and we saw it happened," the source added. "And there's a lot of reason to think he would wind up a significantly weaker candidate than Hillary."
Many of these strategists say that if Biden did win the nomination, they don't think he would have a better chance of defeating Donald Trump than other top-tier contenders such as Kamala Harris or Kirsten Gillibrand - disputing the claim from many Biden supporters that he represents the safe choice in an election when rank-and-file voters are desperate to win back the White House.
"Let's be honest: He's an older white guy," said Jim Cauley, a longtime Kentucky-based Democratic strategist. "Does he connect with the base?"
Cauley considers Biden one of a handful of leading contenders and, indeed, many of those interviewed say the onetime senator still has a chance to win the nomination and would make for a strong general election foe for Trump by potential luring centrist voters and even some Republicans to vote Democratic.
But for a candidate who might expect to enter the race as the favorite, the skepticism could be a wake-up call - particularly coming from a community of men and women that should be naturally more optimistic about a longtime party leader.
"I do think the conversation about him being the front-runner is overhyped, frankly," said Symone Sanders, a Democratic strategist who said she still considers a Biden candidacy "formidable." "Anyone who is front-runner a year out from Iowa, a year out from South Carolina, is a front-runner because of name identification."
Even if he lacks support from strategists, Biden has the encouragement of other members of the Democratic establishment, including Rep. Jim Clyburn of South Carolina (who has said the state would be Biden's to lose) and members of the U.S. Senate. The former senator's supporters dispute that he would enter as anything but a front-runner.
"He was Barack Obama's vice president," said Celinda Lake, a longtime Democratic pollster. "And so there's no question in people's minds he can handle the job, knows the job, can do a good job."
Lake, who said she has not spoken to the vice president personally about a run, cited Biden's strong connection with blue-collar voters, his extensive foreign policy experience, and his evolution on key issues such as anti-crime legislation.
"He's a change agent," she said. "And he's been a change agent for years."
Voters, not strategists, ultimately decide who wins elections, and even the savviest political professionals frequently predict poorly. (Many interviewed for this story joked that hearing so many strategists were pessimistic about Biden made them think he actually stood a better chance.)
And for now, voters are receptive to a Biden candidacy: National polls show him leading the pack while, according to a CNN poll released last week, a strong majority of Democratic voters say they think he should run for president.
The danger for Biden, however, is that these strategists act as a leading indicator for how many voters will ultimately feel about the former vice president after months of a rough-and-tumble campaign. Because while voters might not yet be familiar with Biden's record, the party operatives are - and they worry about what they know.
"He brings a lot to the table in terms of strengths," said Mike Mikus, a Pittsburgh-based Democratic strategist. "But because of his long record in the Senate, unlike a lot of the other candidates, he has a lot more pitfalls that he faces."
Biden's vulnerabilities are myriad, strategists say, and rooted in both his record as a public official and his performance as a candidate. In interviews, strategists mentioned his support for a 1990s crime bill that subsequently came under heavy criticism, his past positions on banking regulation, and his treatment of Anita Hill during Clarence Thomas' Supreme Court confirmation hearing.
They also say Biden will be criticized for less popular parts of Barack Obama's presidency (such as mass deportations) and his insistence even now - at a time when Democratic voters view Donald Trump and the larger GOP as one in the same - that bipartisanship with Republicans is essential. Even his well-known penchant for gaffes, once seen by many rank-and-file Democrats as endearing, will take on a new context amid the harsh scrutiny of a presidential campaign.
Biden might have overwhelmingly favorable numbers among Democratic voters, but the gradual revelation of these details over the course of a campaign will change perceptions.
"There's a huge difference between, 'I want to go to an event with you, I want you to autograph your book, and I want to take a selfie with you,' versus 'I want to vote for you for president,'" said one Iowa Democratic official.
"2016 is going to be felt in the Democratic Party for the next couple decades," the source added. "There is just massive distaste for the whole baby boom generation."
Biden has apologized for both the tough-on-crime legislation and his treatment of Anita Hill. Strategists such as Lake say the apologies will soften any criticism, particularly in the context of a candidate arguing that he embraces a changing Democratic Party and wants to be its next leader.
But given his penchant for off-the-cuff remarks that land him in trouble, Democrats wonder if he'll stick with a conciliatory approach during a long campaign.
"There's a lot that's important to get right these days _ from the way we talk about people or key issues to understanding our own privilege," said one national Democratic strategist, who called it a "strong personal desire" that Biden not run because of the fierce criticism he'll face in a primary. "And that's something he's going to have to face and address. Getting it wrong won't be something he can blow off as a gaffe or 'Joe being Joe.'"
The community of Democratic strategists is large, diverse and rarely agrees about anything. It would be wrong to say that all of them think a Biden run for the presidency is a bad idea, when many interviewed for this story say they think there's more room for a moderate candidate to succeed in a Democratic primary than is widely believed. Others say that in what might become the largest field of Democratic candidates in a generation, they have no idea how to handicap Biden's chances - or anyone else's for that matter.
But even most of the vice president's defenders expressed ambivalence about his prospects, calling him a strong candidate who nonetheless will likely face steeper obstacles than other top-tier contenders. Not one them said they considered Biden a clear-cut favorite to win the nomination.
And perhaps most surprising, most agreed that when it comes to the general election, Obama's running mate doesn't necessarily represent the party's best chance to defeat Trump.
Biden would be a strong candidate, they say, but so would many of the front-runners - in part because they believe the classic formula for a successful presidential campaign has changed in recent years. Whereas once candidates once won by winning over moderate voters, the emphasis now is on which candidate can best drive turnout among the party's electoral base.
"Who can turn out the largest proportion of African-Americans, of Hispanics, of white women under 40, of college students?" asked Morgan Jackson, a North Carolina-based Democratic strategist. "That's how you combat Trump's turnout machine on non-college-educated whites, who are going to turn out in record numbers.
"In a traditional election, it's about the middle," Jackson said. "But with Donald Trump, I don't think the middle exists."