Joe Biden may have opened up a path to a run for the Democratic nomination last night, simply by admitting he doesn’t know if he has it in him to do so. In a lengthy interview with Stephen Colbert on CBS’ The Late Show, the man getting the most mention these days as Plan B to Hillary Clinton did the normal gladhanding and winking at the camera expected on these shows. It got serious when Biden talked about the recent death of his son Beau, saying that “you know you’ve succeeded as a parent when your child turns out to be better than you.”

When pressed for an answer to the question on everyone’s mind, though, Biden stopped winking and joking, and offered a refreshing moment of introspection:

Chris Cillizza writes that this gives a glimpse into why people around Biden have remained remarkably loyal to him over more than 40 years in Washington:

Speaking about his thoughts on a presidential run, Biden, again, offered a decidedly honest take. “I’d be lying if I said that I knew I was there,” Biden told Colbert. “I’m being completely honest. Nobody has a right in my view to seek that office unless they are willing to give it 110 percent of who they are.”

The Joe Biden on display with Colbert is the person who has inspired remarkable loyalty — over decades — from a tightknit group of staffers who would form the core of his presidential brain trust if he decided to run in 2016. It’s the guy who, for a time in 1987, was one of the front-runners for the Democratic presidential nomination. It’s who Barack Obama saw when he decided to pick Biden as his vice president in 2008.

People laugh at Biden, often for good reason, but this quality gets missed in the derision. No one of any stature in the Democratic Party can make an emotional connection like Biden. Not even Barack Obama can do it, at least not in the same way and with the same kind of voters. Obama’s cool approach, outsider status, and identity created strong emotional connections with voters based on their desire for change and to change history. “At that time I was behind the idea of a little bit different president,” one younger New Hampshire voter recently told me. “He was a black president, and I thought that was a good idea. Different point of view. What could that do for us?”

Biden’s emotional connection goes to who people are, and it’s effective because it comes across as sincere rather than an artifice like, “I feel your pain.” People forget this, but Biden gave the most effective speech of the 2012 Democratic convention. It spoke to the older Democratic middle-America coalition, the one Ronald Reagan wooed to the GOP in the 1980 election. Underestimating that impact would be a mistake for Republicans, who should be strategizing on how to get those voters back in the GOP fold.

At the same time, the same sincerity and honesty (more of a lack of filters) gets Biden into more trouble than good, Cillizza admits:

Of course, while those traits served Biden well in his interview with Colbert, there’s plenty of evidence in his political past that suggests that his honesty is a double-edged sword that often cuts more negatively than positively. Clinton is a far more disciplined candidate than Biden and has a more finely tuned ear as to what to say when.

But the lesson of the 2016 election to date is that voters are craving authenticity. They want people willing to level with them even if they don’t like what they are being told. That sentiment is at the core of Donald Trump’s rise and has more than a little to do with the appeal of Bernie Sanders.

If Biden did get in, he’d immediately connect with the voters left behind in the Obama coalition: white working-class voters, perhaps especially in the Rust Belt. But could he keep them, and would that cost Democrats among the younger, more diverse demographics they desperately need to win? Even if Biden managed to keep his foot out of his mouth, a number of factors would work against Biden and the Democrats in the general election: his age (nearly 74 by that time), 43 years in Washington, his support of credit and finance firms, and the weight of the increasingly unpopular Obama administration. However, that’s not much different than Hillary Clinton, who has a lot more personal baggage than Biden.

In other words, he’s beatable, and Republicans shouldn’t worry overly much about his potential entry into the race. But neither should they underestimate his potential appeal. This kind of honest self-reflection hasn’t exactly been a feature in either primary, and that kind of authenticity and personal vulnerability has a lot of appeal over vanity, entitlement, and narcissism.

Joe Trippi thinks a Biden run would be “disappointing,” but if Obama went all in on endorsing him, that might change things — in the primary:

Citing a recent Quinnipiac poll in Iowa (which showed Biden at just 12 percent), Trippi, a Fox News contributor and Democratic strategist, concluded that the hype is overwrought: “If they’re really looking for an alternative to Hillary Clinton,” he said of likely Democratic caucusgoers, “it doesn’t seem to me that the guy they’re looking for is Joe Biden.”

Trippi concedes that Biden has earned the right to run, and that there is one possible exception to his theory: “Is Barack Obama prepared to go out and campaign side-by-side with him?”

Republicans would have a field day with that. Voters barely went along with a second term for Obama in 2012. They won’t want a third Obama term in 2016. Biden could win the primary that way, but Democrats would end up losing the general election — especially if Republicans nominate a younger, energetic candidate who can speak to the demographics that will be remarkably uninspired by the Democrats’ Baby Boomer bench.