At Joe Biden’s kickoff rally, in Pittsburgh on Monday, the long line that stretched around the Teamsters’ union hall, snaking downhill past newly desirable row houses in the trendy Lawrenceville neighborhood, was not as homogenous as many might have imagined. If men outnumbered women, it wasn’t by much, and the crowd included plenty of chatty millennials. The folks were predominantly white, to be sure, and it was the kind of crowd that makes reporters look fussily dressed. But any unwelcome similarities to a Trump rally in the Rust Belt pretty much ended there—not just because these folks were mostly pleased to chat with those reporters, rather than holler at them, but because they were, to one degree or another, skeptical of the candidate they’d come to see.

Alice Elash, a teacher, who came to the rally with her friend Ruth Close, proclaimed, “Blue collar for Joe!” But she also had her doubts: “I still have an open mind about who my candidate will be.” Close added, “One thing we are concerned about is his age. Hearing him speak and everything, he is a little slower than we’d want—just being honest about that. Of course, the guy who’s in there now just works two hours a day, so . . .”

Another pair of friends, Patricia Jakiel and Marsha Williams, who both work in mental-health care, wore homemade “Joe 2020” stickers. But they had made their decision to endorse Biden more out of pragmatism than runaway enthusiasm. “I’m liberal,” Jakiel said. “I’d go left this year. In fact, I’d go way left, but we’ve got to pick the person who can get Trump out of there. That is the priority. And it’s going to take a white male with experience. That’s just the way it is.”

Others were in attendance not so much for Biden but out of loyalty to the International Association of Fire Fighters, which had endorsed him earlier on Monday. Brendan Clarke, wearing one of the ubiquitous yellow “Fire Fighters for Biden” T-shirts, was yukking it up with some of his fellow union members. “Yes, yes, we’re all firemen for Biden,” he said, and laughed. A lifelong Democrat, Clarke voted for Trump in 2016. “I didn’t like Hillary,” he explained. “And now I’m not as upset as others.” I asked him what he thought of Trump’s tweets that morning, which claimed that, although “Dues Sucking” union leaders might be for Biden, the rank and file were with the President. “I didn’t know he said that,” he responded. “But I would say that more membership is for Trump than would be expected. For now, I’m going with the union. But it’s a nice day—what I really want is to get back out on my motorcycle.”

By starting his campaign in the Rust Belt, where he is supposed to have the greatest appeal, Biden might have hoped for a relatively easy sell. But just about everybody had something she wanted—or needed—to hear. For some, it was what Biden would do about climate change. Others said that they hadn’t heard enough about immigration or health care. Mostly, though, Biden’s name recognition and many years in the political spotlight have both blessed him with a steady lead in the early polls and cursed him with a whole mess of explaining to do.

Ever since it became clear that he was going to take the plunge into this year’s crowded race, Biden’s record, stretching back to the nineteen-seventies, when he opposed “forced busing” to integrate public schools, has provided ample evidence that the front-runner might be out of tune with the mores of the party he wants to lead. He’s had no choice but to address the controversy over his treatment of Anita Hill during the Clarence Thomas confirmation hearings, in 1991, along with the fresh accusations that he’s made women uncomfortable with his physically intimate style of politicking. But he’s failed to put either problem to rest, and hasn’t attempted to explain other parts of his past, including how he urged Ronald Reagan to ramp up the war on drugs, in the nineteen-eighties, or his support for the nineteen-nineties crime bill that led to mass incarceration, particularly of African-American men. It’s hard to nudge your story forward when the past, including Biden’s years as Obama’s faithful sidekick, won’t let go. “Everybody knows him,” Laura Shimko, a mother of two who is in her thirties, and who has eighty thousand dollars of college debt, told me. “He’s a genuinely kind person, and I’m all for him. But, still, I’d like to hear: What will you do that maybe differs from your Administration with Obama?”

Down the hill, Cris Forelli, who’d come out with fellow-students from the University of Pittsburgh, said that it wasn’t Biden’s physical age that worried him so much as his political age. “It’s less about his psychological capacity to serve the office,” he said, “but more the points of view that an older person would have. His first senatorial term was in the nineteen-seventies, right?” Forelli’s friend, Jamiya Burton, said that Biden won’t get far unless he does a better job of explaining his past treatment of women, including Hill. “He needs to make a statement,” she said. “Just brushing it under the rug and expecting it to go away—it’s not. We’re young women, and, of course, it’s one of the first things that comes up all the time.”

Once most of the folks had made it inside—a few hundred couldn’t be squeezed in—Biden took the stage to the strains of Bruce Springsteen singing “We Take Care of Our Own.” Pushing up the sleeves on his blue button-down shirt, Biden, whose wife had helped warm up the crowd, began with an old quip: “My name is Joe Biden, and I’m Jill Biden’s husband.” That set the tone. Biden wasn’t so much redefining himself as reasserting himself. He thanked several local union leaders by name, then ticked off a succession of labor groups, as if to demonstrate his powers of memorization. “By the way,” he added, just in case there were any doubters, “I make no apologies. I am a union man.”

The roll call of unions was as close as he came to offering concrete specifics. Biden called for a fifteen-dollar minimum wage and to repeal last year’s “tax cut for the very wealthy,” supported “a public-option plan for Medicare,” and talked about “clean, renewable energy,” but he hadn’t come to unfurl any bold new policy positions. He’d come to lay claim to the working-class Rust Belt voters whom his supporters say he can win back from Trump, in states like Pennsylvania, in 2020. “Pittsburgh, and my native town of Scranton, and my home town of Wilmington and Claymont, they represent the cities and towns made up of hard-working middle-class Americans who are the backbone of this nation,” he told the crowd. “That’s not hyperbole. The backbone of this nation. And I came here because, quite frankly, folks, if I’m gonna be able to beat Donald Trump in 2020, it’s gonna happen here.”

This was comfortably familiar terrain for Biden, literally and metaphorically. Like every centrist Democrat, he’s been paying homage to the middle class for decades now, even as it’s dried up and threatened to disappear. He’s told the stories he told on Monday—two about his dad, in particular—so many times that political reporters (and his fans) can practically recite them in their sleep. He’s lit up union halls for decades with resounding denunciations of corporations and lofty calls to restore the “dignity of work.” Maybe it was a sign that Biden, as Frank Rich wrote recently for New York magazine, “has a comfort zone as predictable in its septuagenarian ways as Trump’s rounds of golf at Mar-a-Lago.” Maybe it was a strategic recognition that, unlike Bernie Sanders or Trump, Biden’s numbers don’t reflect a base of people who are sold on him but a bunch of voters who see him, at this juncture, as “most electable”—and need to be turned into a cadre of firm supporters. It’s also possible that the famously mistake-prone candidate decided to lead with his strengths. And those should not be underestimated.