Jordan Gale / Reuters

Say what you will about Joe Biden, but you can’t accuse him of pessimism.

Speaking at a fundraiser on Monday, the former vice president and current Democratic front-runner said that Republicans in Congress will soon be ready to work across the aisle once again.

“With Trump gone, you’re going to begin to see things change. Because these folks know better. They know this isn’t what they’re supposed to be doing,” Biden said. Yet on Tuesday, barnstorming in Iowa, Biden told audiences that Trump is “an existential threat.”

These ideas point to the contradiction at the heart of Biden’s campaign. On the one hand, Biden is—more stridently than most of his Democratic rivals—running a campaign against Trump. While some of the other candidates see Trump as merely the apotheosis of long-running trends in American society toward xenophobia, isolationism, plutocracy, and kleptocracy, Biden sees Trump as aberrant. This allows Biden to offer a nostalgic campaign, which, as I have written, is itself an aberration among Democrats historically: Vote for me, and we’ll put things back the way they were.

Biden said Monday, “Four years of this president will go down as an aberration … Eight years of Donald Trump will fundamentally change who we are in profound ways.” How can it be that Trump poses an existential threat, and if he serves two terms, it would produce a profound shift in American society, but that if he serves only four years, it will be easy to return to the supposed idyll that existed before 2016? The idea beggars belief.

There’s no question: It’s a lot easier to reverse four years of policy than it is to reverse eight years of policy, as the Trump administration has shown. Trump has managed to roll back some of Barack Obama’s policies, especially those instituted through executive action during his second term. But the Affordable Care Act has proved very difficult to dislodge, despite a months-long frontal assault that consumed much of Trump’s first year in office.

But Biden isn’t really talking about policy, is he? He’s talking about the sense of despair and frustration that seems to suffuse much of the country today—a spirit that animated some Trump voters to support him in 2016, and has animated many of those who voted against him ever since. It’s different from policy, though it is inextricably related: You don’t get family separations at the border without the cruelty-driven worldview of the administration.

He’s also talking about the way Republican officeholders are behaving, which is another essential ingredient to Trump enacting his agenda. Biden has previously promised that GOP members will have an “epiphany” once Trump is out of office (and, presumably, Biden is in). “This ain’t your father’s Republican Party,” Biden said Monday. If your dad is Biden’s father’s age, or even Biden’s age, that’s true. If your father is younger, it probably isn’t. As political scientists have shown, both parties have become more ideologically homogeneous and polarized in recent decades, but the Republican Party has become especially polarized. (By some measures, the process started in the late 1970s, just as Biden was finishing his first term in the Senate.)

Despite the inexorable process of polarization, Democrats continue to insist that Republicans will embrace bipartisanship any moment now. Seven years ago this month, Biden’s old boss told supporters at a rally that everything would work better after the 2012 election: “My expectation is that if we can break this fever, that we can invest in clean energy and energy efficiency because that’s not a partisan issue.” This didn’t happen. The idea that it would be more likely after a Biden victory over Trump is even more far-fetched, given that the process of polarization has continued another seven years, and given the passions that Trump arouses.

One needn’t accept the deep historical critiques of American society leveled by Elizabeth Warren and Bernie Sanders to acknowledge that Republican polarization isn’t a Trump-era phenomenon. Trump represents a culmination of the process, rather than a swerve away from it. The Republican Party will not always be the party of Trump, but it will never again be the party of Bob Dole. (Democrats back then denounced Dole as an extremist, too, of course. It’s never going to be the party of Howard Baker either.) Meanwhile, Trump has catalyzed the polarization of the Democratic Party as well.

This is not to say that the specific actions the president is taking won’t have a lasting impact of their own. Even if Trump doesn’t win reelection, his actions will reverberate for years to come, though it’s difficult to predict which ones will have the greatest influence.

Some of the effects are murky: No one knows what the long-term impact of Trump winking at foreign assistance to win elections, discarding conflict-of-interest rules, or knocking down any number of norms will be. Others are more concrete. Alliances that were shaken by the George W. Bush administration and haltingly rebuilt under Obama will be harder to repair after a second rupture. Trump’s judicial nominees will shape American jurisprudence for a generation. The conservative media have been remade. Dozens of Republican candidates are running in different proportions on Trump’s style and substance. His current aides will populate government for decades to come. (Consider how many alumni of the Reagan administration, so far away from Trump in many respects, work for him: Attorney General Bill Barr, National Security Adviser John Bolton, the Venezuela envoy Elliott Abrams.)

If Biden’s “existential threat” language sounds familiar, that’s because Hillary Clinton mounted a similar argument against Trump in 2016. It was an attempt to meet fire with fire: Trump was campaigning by trying to spread fear, and Clinton offered her own dose of fear in response. Anat Shenker told Molly Ball that Clinton risked merely amplifying Trump’s message. Can Biden have more success? Maybe he can: After all, the dangers of a Trump presidency are no longer hypothetical but concrete. That only underscores, however, how impossible a task reclaiming the old “normal” really is.

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