Read: The establishment strikes back

The midterms are the model to follow in the general election, says Meredith Kelly, a Democratic strategist and DCCC veteran. “Whoever the nominee is will have the excitement of the base—that is driven by Trump,” she says. “So then you need to look for the candidate that can build on that and bring in more people” such as moderates, independents, and even some Republicans. This, she says, “is a pattern that works in the era of Trump.”

Democrats’ pivotal wins in 2018 were in places such as Virginia’s Seventh and Tenth Congressional Districts, where Abigail Spanberger and Jennifer Wexton, respectively, defeated Republican incumbents and helped secure the Democrats’ House takeover. Last week, in addition to his overwhelming support among black voters in states such as Alabama, Biden won in these exact districts—and similar ones across the country—when he crushed Sanders in 10 of 14 state primaries. Turnout in Virginia, where the former vice president won by 30 points, increased dramatically from 2016, and Biden defeated Sanders with high margins in the suburbs of Washington, D.C.

“One of the things that we saw in 2018 was a particular mobilization of college-educated, upscale, suburban professionals in large metropolitan areas—a lot of the seats in Congress that flipped in 2018 were centered in those sorts of places,” says Dave Hopkins, a political-science professor at Boston College. Last week, that group “united very quickly behind Biden.”

“You will see Joe pick up lots of swing districts across this nation as we move forward across other contests,” argues Representative Terri Sewell of Alabama, one of the vice chairs of the moderate New Democrat Coalition, who has endorsed Biden.

The so-called majority makers from 2018—people such as Spanberger and Wexton—aren’t identical to Biden: Many of them are young; many are women; and most arrived in Congress with little to no political experience. But they do have similar sensibilities: They’re center-left, not lefty-left. They promised to promote unity and bipartisanship, welcoming the support of former Republicans and more moderate independent voters. They pledged to pursue a staunchly Democratic agenda—expand health care, address climate change—without a political revolution. Sixteen of them have endorsed Biden for president. Theirs are “the ideas that Biden is advocating,” says Representative Ami Bera of California, the chair of the fundraising arm of the New Democrat Coalition, who has endorsed Biden. “The way he talks about [politics] is the way Spanberger … or [Representative Elissa] Slotkin talk about it.”

Read: Bernie Sanders meets his biggest threat

Representative Alexandria Ocasio-Cortez and a handful of other progressive freshmen were the most high-profile members elected to Congress two years ago, but progressive candidates overall didn’t fare as well as the more moderate ones. Neither did they on Super Tuesday, when down-ballot Democrats endorsed by Sanders and backed by progressive groups such as Justice Democrats lost their primary elections in multiple states.