Today, dear reader, we’re going to discuss Bernie Sanders in 2020. I’ll try to steer clear of the Democratic primaries of 2016, which no one on the left wishes to relitigate yet no one on the left can resist relitigating. The associated questions cut to the core of the Democratic Party’s internecine disputes: Do we need to win back Trump voters, or do we need to ditch them and find some new ones instead? Should our priority be to reduce economic disparities or to reduce racial disparities—and how are the two issues related? If you want to cause fistfights, ask those questions in a crowded liberal room and then, for your own safety, leave.

Meanwhile, Democrats are maneuvering and calculating. The latest news from the Democratic National Committee is that its chairman, Tom Perez, has moved to purge allies of Bernie Sanders. An army of Hillary supporters is still fighting the last war over her legacy, as the tide turns against a Bloombergian centrism that, fairly or not, has come to define the Clinton brand. California Senator Kamala Harris has decided to throw her lot in with Bernie on single-payer health care, as have a half-dozen other potential presidential contenders.

Bernie, for his part, shows few signs of slowing down. He has announced he is running for re-election as an Independent in 2018. He is participating in rallies. He has made two trips to New Hampshire in as many months. And, most important, he is tending to his grassroots army (something he wishes Barack Obama had done). During the 2016 primaries, I underestimated Bernie Sanders, but I learned my lesson, coming to see how tough the man was after all. As we look ahead to 2020, Bernie Sanders might be Trump’s strongest opponent.

Sanders has several obvious advantages. People know him. He has good approval ratings—53 percent favorable, according to a recent Harvard-Harris poll. He’s been through a lot of the process. He is also leading the polls of New Hampshire primary voters, with support of 31 percent, followed by Joe Biden at 24 percent. But it’s the less obvious advantage that’s going to be our focus. While Bernie represents the left of the Democratic Party (even as an Independent), he’s culturally conservative on a few key issues. That makes him uniquely positioned to move—at least a little—to the right and win back some of the support Trump gained.

We’ll never stop debating what happened in 2016. But if we look at the numbers, we can see that Trump was playing to pent-up demand. Nearly a third of Americans, it turns out, are conservative on social issues but liberal on economic ones. Until Trump came along, they didn’t have an obvious candidate. (A report released by the Democracy Fund Voter Study Group this summer, authored by New America fellow Lee Drutman, makes the numbers clear, particularly in Chart 2.) They were populists forced to choose between what they saw as lousy economic policy from Republicans and lousy social policy from Democrats. They might be the type who were, say, fine with Obamacare but unhappy with new gun laws or school-bathroom regulations.

Donald Trump played to this neglected group of Americans and implicitly offered to revive the New Deal from the right, defying the economic and foreign-policy orthodoxies of the Republican Party and moving left on a few social issues. It was an unprecedented feat of political audacity. What we’re likely to see by 2020, however, is that Trump was too in sync with the donor class to fulfill his promises in practice. He has been willing to throw poorer Americans to the wolves on consumer protections and health care and workplace rights. This week, the White House moved one step closer to advancing a multi-trillion dollar tax cut, even as it undid Obama-era consumer protections against credit card giants. It also declared an opioid crisis but suggested no funding for doing anything about it. Many of his supporters, especially those who voted for Barack Obama in 2012, may be up for grabs once more.