Why? Because in a big primary field, with a lot of flavors available to voters, it’s very hard to hold your base if you aren’t giving that base a clear reason to vote for you. And the only reason anyone would affirmatively want to vote for Biden is the same reason so many liberals now despise the very idea of his candidacy: because he has that moderate record, because he’s closer to the political center than many of his critics, because he’s out of step with what Matt Yglesias of Vox recently called “the Great Awokening” — the sudden leftward turn on issues of race and immigration and identity.

The key point here is that while the Great Awokening has transformed the Democratic Party, it hasn’t entirely eliminated the constituency for a Bill Clintonian form of moderation. The party has embraced left-wing ideas about structural racism, but there are still lots of Democratic voters — minority voters included, as white liberals have outpaced blacks and Hispanics in their wokeness — who would endorse the rhetoric of personal responsibility and colorblindness that the party’s activists now disdain as “respectability politics.” The party is more zealously pro-choice than ever, but there are still Democrats who identify as pro-life; the party is vigorously pro-#MeToo, but there are still Democrats (the Al Franken constituency and others) who worry that the movement has gone too far.

And that’s just social issues: You can find similar constituencies who aren’t yet sold on the full social-democratic agenda, who still find the old Clinton-era mix of middle-class tax cuts and targeted spending more appealing than the Bernie Sanders turn.

These groups — a mix of older white Democrats, culturally moderate African-Americans and Hispanics, and anti-Trump suburbanites — probably don’t amount to a primary-season majority. But they might add up to a large plurality in a divided field, which could easily be enough to win the nomination. (It’s how Sanders will win it, if he does — with a very different plurality, of course — and it’s how Trump won the Republican nomination in 2016.)

To unite this plurality, though, Biden would have to actually appeal to them openly and directly, which would require taking ownership of his record: not defending everything, not avoiding all apologies, but arguing explicitly that some tough-on-crime policies were a necessary response to a destructive multi-decade crime wave, that some moderation on abortion should be acceptable in the Democratic Party and that the Ocasio-Cortezan turn on economic policy should be questioned or resisted. And, yes, defending his personal familiarity, hugs and nose-rubs and hair-kisses and all, and in the process questioning some aspects of #MeToo.