Just go back to that August day in 2016 when, after endorsing Hillary Clinton in Scranton, Pennsylvania, he took her to the house he grew up in to show her the kitchen where his grandfather used to sit and stress about finances. He was soon bounding around the neighborhood shaking hands, trying to draw people into conversations, while Clinton was left standing on his old front lawn deflecting a question about why so many in the area were supporting Trump.

Or last year, when Abby Finkenauer’s congressional campaign persuaded him to make a trip to Iowa, despite his attempts to avoid stoking presidential speculation by appearing in the state. Finkenauer insisted to his team that he could make the difference in swaying suspicious swing voters to back a Democratic woman in her late 20s (she won, narrowly).

Or maybe the idea that he’s a magnet for white working-class votes is yet another bit of conventional political wisdom that’s about to be blown apart. Beyond two previous presidential runs that barely got off the ground, he’s never run a race on his own outside Delaware, and the last competitive race he had there was his first one, when Richard Nixon was president.

“We strongly believed that he would be a help in the industrial Midwest, and we used him there a lot,” said David Axelrod, the top Obama adviser who helped bring Biden onto the ticket in 2008. Whether he was, in the end, a help in the industrial Midwest, Axelrod said, “that’s so hard to say.”

Joe Biden: ‘We are living through a battle for the soul of this nation’

“Watching him campaign, it does strike me that he could campaign in all 88 Ohio counties and break through with people,” said Ohio’s Democratic Party chairman, David Pepper. He added, “I think people are too quick to make a set of assumptions about one candidate and assume that others couldn’t do it.”

While Biden is a tighter demographic fit for the white working-class voters whom the Democrats want to win back, the last Democrat to comfortably win the Iowa caucuses and go on to win Ohio, Indiana, Wisconsin, Michigan, and Pennsylvania in a general election was a half-Kenyan, half-Kansan from Chicago by way of Hawaii.

Biden certainly wanted to believe on Tuesday morning that he was reaching people in their guts, looking out from the stage in the basement of a Capitol Hill hotel at the International Association of Fire Fighters union convention, which has essentially pre-endorsed him, handing out free Firefighters for Biden T-shirts to members after the speech. It was a crowd full of Run Joe Run signs and chants from a mostly white crowd. He spoke emotionally about collective bargaining, fair pay, standing up against the people who want to warp the country toward the rich, and the crowd responded.

Steve Clemons: One last trip with Joe Biden

“I appreciate the energy when I came up here. Save it a little longer—I may need it in a few weeks,” he said. With an introduction by his wife and a cheerleading introductory video, the event was a dry run for what a campaign announcement might be like. “Be careful what you wish for,” he said. “Be careful what you wish for.”