After a wildly depressing year both at the ballot box and in the halls of Washington, Tuesday was a banner night for Democrats and progressives nationwide. Liberal and centrist candidates won a slew of surprising and significant victories from Virginia to Montana on Election Day. Since then, few on the left have crowed louder than the Democratic Socialists of America, who won 15 races across the country, bringing the current number of elected DSA members to 35. In keeping with previous wins, all but one of these triumphs were in races for local office. The exception: 30-year-old Marine veteran Lee Carter’s underdog 9-point victory in Virginia’s 50th district House of Delegates race against sitting Republican Majority Whip Jackson Miller.

Carter filed to run for the seat all the way back in February 2016, and he has said his campaign was motivated by a work injury he suffered in 2015 and the frustrating interactions with the Virginia Workers’ Compensation Commission that followed. Upon entering the race, Carter ran as a Democrat, but he opted out of submitting regular reports about his campaign to the state party. In October the Richmond Times-Dispatch reported that party leaders cited this choice as an explanation for their unwillingness to fully back him. But the Times-Dispatch’s Patrick Wilson suggested the party spurned him in part because of his opposition to Dominion Power, a regulated monopoly that’s planning a local natural gas pipeline and a power line, and which donates heavily to state Republicans and Democrats. Ultimately, the state Democratic Party became one of Carter’s top three donors, along with Forward Majority Action, a super PAC led by Obama campaign alums aimed at flipping state legislatures, and the Let America Vote Victory Fund, a group founded by former Missouri Senate candidate Jason Kander.

On the ground, Carter’s campaign was boosted by regional chapters of the DSA. His campaign was run by a member of D.C.’s chapter, which actively volunteered for Carter alongside other Virginia chapters. Carter—who sang the worker’s anthem “Solidarity Forever” at his victory event on Tuesday night—was never shy about his membership in the group. Republicans attempted to seize on this with a mailer depicting a wild-eyed Carter as the last in a lineup of communist figures including Joseph Stalin and Mao Zedong.

Conservatives sent out this red-baiting, meme-based mailer attacking @DemSocialists candidate Lee Carter AND HE JUST WON HIS ELECTION ANYWAY pic.twitter.com/tfieQ04gxS — Annie Shields (@anastasiakeeley) November 8, 2017

In fact, the figure most relevant to Carter’s personal politics is Bernie Sanders, whose presidential campaign inspired him to join the DSA just last year. “He went out there and said, ‘I’m a democratic socialist. Here’s what that means: It means I believe in strong unions, health care for everybody, and an end to discrimination,’ ” Carter told the New Republic’s Graham Vyse. “Well, that’s what I believe in, too.”

Definitionally, those goals don’t fully constitute democratic socialism proper, which the DSA envisions as a fundamental transformation of the American economy—with most firms becoming democratically run by workers and certain key industries like health care and housing being taken out of the private sector entirely. But Carter is likely ideologically representative of most who have swelled the DSA’s ranks almost fourfold since last year to 30,000 members.

Of course, Tuesday night was a good night for progressives and Democrats of all stripes, including Virginia’s governor-elect Ralph Northam, who defeated progressive challenger Tom Perriello in the primary and was criticized from the left for responding to Republican Ed Gillespie’s immigration rhetoric by saying he would support a bill banning sanctuary cities.

The most obvious takeaway from Tuesday’s results is that Trump and Republicans in Washington have energized Democratic voters—the 40 percent plurality of Virginia voters who were primarily motivated by health care according to exit polls, for instance, broke overwhelmingly for Northam, indicating Republican efforts to repeal Obamacare probably had a significant impact on the race. The wins suggest that progressives and centrist Democrats alike will be in good shape for next year’s midterms. But the question of how Democrats and progressives can expand the voting constituency for their policies and build lasting power beyond the next few elections—not just in Congress, but in races like Carter’s for state legislative seats around the country—is still a live one. The DSA and its supporters have insisted for months that moving left is the answer. In Carter, they have a data point suggesting, at the very least, that doing so won’t necessarily hurt.