LZ Granderson is a journalist and political analyst. He was a fellow at the Institute of Politics at the University of Chicago and the Hechinger Institute at Columbia University. He is the sports and culture columnist for the Los Angeles Times and co-host of ESPN LA 710's "Mornings With Keyshawn, LZ and Travis." Follow him on Twitter and Instagram @lzgranderson. The opinions expressed in this commentary are solely those of the author. View more opinion articles on CNN.

(CNN) Sen. Kamala Harris is gone, Mayor Pete Buttigieg has risen, Sen. Elizabeth Warren seems to have lost her momentum, and overlooking the shuffling deck from on high is former Vice President Joe Biden, who was the favorite before he was even a candidate.

LZ Granderson

In many ways, voters' preference for Uncle Joe harks back to a time when a party's nomination often seemed predetermined once a candidate had put decades into public service and grown his or her name recognition. You know: 'so-and-so has been around for x number of years — it's his turn.'

The election of President Barack Obama sparked a change in that model, while President Donald Trump set the whole thing ablaze. Clearly, Democrats are willing to swing the pendulum back the other way, first with the party's chosen nominee in 2016, Hillary Clinton, and now with frontrunner Biden — although the latter comes with a curious caveat.

For as much as Biden, who was first elected to the Senate in 1972, touts himself as the man who can restore dignity to the White House, the truth is he is a behavioral and rhetorical wild card as well.

Take his recent confrontation with a voter at a campaign event in Iowa. The man accused Biden of placing his son, Hunter, with a Ukrainian gas company "in order to get access to the president" (he was referring to Barack Obama) — an accusation for which there is zero evidence. The way Biden handled the moment was Trumpian. He called him a "damn liar" and later said, "You're too old to vote for me." He even challenged the man to a pushup contest. I repeat: a pushup contest.