Biden wouldn’t need to pivot so dramatically to be a transformative progressive president. There are plenty of bleak moments in his record, including his treatment of Anita Hill and his Iraq war vote, but it’s not quite as reactionary as leftists sometimes imagine. Among other things, he’s long been better-than-average on unions; as Jared Bernstein, Biden’s former chief economist, told me, “One of the main things that differentiates Biden from a traditional mainstream Democrat is his understanding of the importance of worker power.”

Still, it’s clear that he’s moving leftward. Biden recently came out for tuition-free college for students whose families earn less than $125,000. He endorsed Elizabeth Warren’s bankruptcy plan, something that would have been unimaginable in 2005, when Warren, then a Harvard law professor, charged onto the public stage to fight a regressive bankruptcy bill that Biden supported.

After long supporting the Hyde Amendment, which bans federal funding for most abortions, Biden gave in to pro-choice pressure to come out against it. His climate plan already went beyond any of Barack Obama’s initiatives, and he’s pledged to make it even more robust. Biden’s health care proposal falls far short of single-payer, but it is, as Paul Waldman wrote in The Washington Post, “surprisingly liberal.”

It will be in Biden’s political interests to try to make good on these commitments. “I’ve worked with him for a while now,” said Jared Bernstein. “He really believes you achieve political success by either doing what you’ve promised to do or getting caught trying like hell.”

In the 20th century, the two presidents with the most substantive records of progressive accomplishment were Franklin Roosevelt and Lyndon Johnson. Liberals nearly revolted on the Democratic convention floor when John F. Kennedy, looking to placate Southern voters, chose Johnson, but he ended up doing far more for liberalism than Kennedy did.

Roosevelt’s future greatness wasn’t obvious to all when he first ran for president. Sounding some of the same notes as Biden’s critics today, the famous political columnist Walter Lippmann wrote: “He is no tribune of the people. He is no enemy of entrenched privilege. He is a pleasant man who, without any important qualifications for the office, would very much like to be president.”

It may be too much to hope that Biden could equal the achievements of Roosevelt or Johnson. But should he become president, he will, like both of them, inherit a country deep in crisis, where once inconceivable political interventions suddenly appear possible. We can’t know whether he will rise to the opportunity — only that presidencies are shaped by far more than the ideology of the person who achieves the office.