There’s been some reporting that Donald Trump has privately expressed worries about facing Joe Biden in a general election. But, publicly, the two men seem to enjoy jawing at each other like a pair of prizefighters. “Look, folks,” Biden told a crowd in Davenport, Iowa, on Tuesday night, gripping his podium with both hands. “He denies there’s climate change. What’d he tell Piers Morgan in an interview recently? He said, ‘Well, weather goes both ways.’ ” Biden paused, letting the crowd laugh. Earlier in the day, Axios had picked up on the fact that Biden’s prepared remarks referenced Trump seventy-six times. This proved irresistible bait for the President. “His whole campaign is to hit Trump,” Trump told reporters outside the White House, before setting off for Iowa himself. “When a man has to mention my name seventy-six times in a speech, that means he’s in trouble.” Biden, the President said, is “a loser.”

Before Biden entered the race, in April, many of the leading candidates weren’t talking much about the President. Trump’s disorienting political position—he looks strong or weak, depending on the angle—allowed everyone, from senators to midsize-city mayors and coffee moguls, to see themselves as his potential replacement. But, in the campaign’s early days, the top candidates—Bernie Sanders, Elizabeth Warren, Pete Buttigieg, Kamala Harris—spent much of their time either introducing themselves to the public or offering a range of diagnoses and prescriptions for the chronic ailments of the country. Even today, as William Finnegan recently reported, Beto O’Rourke doesn’t talk about defeating Trump as much as he could, even though it’s a guaranteed applause line at campaign stops.

Biden, by contrast, made Trump his focus from the start. His campaign slogan is “Our best days lie ahead.” It might instead be “Let me at ’em.” In his launch ad, Biden called for a break with this “aberrant moment” and treated the President’s “very fine people on both sides” response to the white-supremacist rally in Charlottesville, Virginia, as a singular moment of intolerable Presidential behavior. Whereas some of his opponents have sought to situate Trump within broader currents of racism, nationalism, or conservatism, Biden has shown a willingness to isolate Trump, particularly from the Party that enables and supports him. “With Trump gone, you’re going to begin to see things change,” Biden said on Monday, speaking about Republicans in Congress. “Because these folks know better. They know this isn’t what they’re supposed to be doing.” (Do they though? Mitch McConnell didn’t need Trump to stonewall Merrick Garland’s Supreme Court nomination.)

Biden isn’t just notable for the way he talks about Trump. He’s also notable for the way he talks about Trump’s predecessor. While the activists and new faces in the Party wrestle with the conciliatory, incrementalist aspects of Barack Obama’s legacy, Biden’s candidacy is explicitly premised on nostalgia for his old boss. “I was proud to work with him,” Biden said in Davenport. “If you didn’t instinctively miss him, Trump sure reminds us of why we need him back—somebody like him.” There’s been a debate in the press about whether Biden is the electability candidate, the person people will vote for because they think he can win. But Biden, for all his strengths, has some real and obvious vulnerabilities as a candidate, from his age to his indiscipline as a public speaker to his recently apologized-for habit of getting uncomfortably close to people. Surely the paeans to Obama are intended to help voters with reservations about Biden’s record—on race, crime, abortion, war—look past them. Rather than debate electability, which is a slippery concept, it might be simpler to think that, if you want a campaign about Trump, Biden’s your guy. If you want a campaign about climate change, health care, or inequality, you should probably look to somebody else.

And where does Trump himself fit into this? The fight with Biden, and the coincidence of their visits to Iowa, somewhat obscured the President’s trip to the state. Insults and vitriol aside—in addition to “loser,” Trump called Biden a “dummy” and various other things on Tuesday—the President’s visit betrayed a concern about shoring up his political support in the state. The effect that Trump’s tariffs have had on Iowa’s agricultural industry—particularly on soybeans and pork products—has been a regular topic at Democratic campaign stops during the past few months. Trump’s remarks at an event in Council Bluffs offered a scrambling kind of rebuttal. “Within a year and a half, I would say, you’ll be in the best position you’ve been in in fifteen years as farmers,” Trump said. “We are turning it all around and we’ve turned it all around and wait until you see the real numbers start coming in when it all comes together.”

Here, again, it was hard to read Trump’s position. Was he making desperate promises because he is weak, or does his willingness to make desperate promises make him strong? Iowa voted for Obama twice, then went for Trump, by some ten points, in 2016. Biden wants to tell people that they can’t afford four more years of this President. Trump is saying, Just wait—you’ll see.