Joe Biden's unique trait as a politician is -- and always has been -- his honesty. Sometimes that honesty gets him into varying degrees of trouble. Sometimes it makes it seem as though he's the closest thing to a real person you could possibly hope for in politics.

Biden's appearance with Stephen Colbert on "The Late Show" Thursday night was one of those latter moments. Colbert, known mainly for the faux conservative he played on "The Colbert Report," largely avoided playing for laughs -- asking Biden to talk about the death of his son, Beau, as well as how he was approaching the decision on whether to run for president in 2016.

Biden was remarkably frank -- on all fronts -- and, according to the pool report, choked up several times during the interview. "No one owes you anything," Biden said of how he is dealing with the loss of his son. "You've got to get up. And I feel like I was letting down Beau, letting down my parents, letting down my family if I didn't just get up."

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.

It's also someone who would drive a striking contrast with Hillary Clinton on the campaign trail. Where Clinton is struggling with the perception that she is neither honest nor trustworthy, Biden is all honesty. Where Clinton is cautious and closed off, Biden is spontaneous and an open book.

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.

The Biden who sat with Colbert on Thursday could have real appeal to an electorate looking for honesty. If he runs, that is.

This post has been updated.