After an unexpected surge of first-time Democratic candidates won 15 seats in Virginia’s House of Delegates last year, the state quickly expanded Medicaid—a shining example of why the party should invest in state legislative races again, after losing almost 1,000 seats during Barack Obama’s presidency.

Moreover, the Virginia surge keeps on giving. It’s partly why Democrats could pick up as many as four seats in Congress there on Tuesday. In Virginia’s long-red seventh district, right-wing economics professor Dave Brat knocked off House majority leader Eric Cantor in a Tea Party surprise in 2014 and won reelection by 15 points two years later. But this year, former CIA agent (and Girl Scout troop leader) Abigail Spanberger is effectively tied with Brat—a development that her campaign partly attributes to the wave of organizing around those statehouse races last year. Democrats picked up three seats in Brat’s district, and two of the winners, Debra Rodman and Dawn Adams, were underdogs who ran insurgent, people-powered campaigns to defy the odds.

“That laid the groundwork for this campaign,” says Spanberger’s communications director, Justin Jones. “They knocked doors that hadn’t been knocked in years, they identified voters that had never talked to Democrats before. Now we have all these small neighborhood organizations that are hosting events and fund-raising for us. It made a huge difference.”

Nationally, Democrats professed to learn the lessons of Virginia earlier this year: State legislative races matter, and you can’t win if you don’t play; first-time candidates need tailored assistance; money matters, but not as much as for federal offices; down-ballot races can contribute to top-of-the ticket success, and the party has to put them in action all over the country in 2018. Have they? Late reporting from the field says yes—but there’s plenty of room to improve and ramp up in 2020.

To recap, in 2010, Democrats held a majority of the 100 state legislative bodies. After Obama’s 2008 election, Republicans focused on taking back statehouses with Operation Redmap, pouring millions of corporate dollars into normally sleepy state races. It worked. Today, Republicans hold 67 state chambers. The good news is that Democrats are finally fighting back effectively, fielding the most state legislative candidates in 36 years. Of the 6,066 state legislative races on Tuesday, more than 5,300 feature Democratic challengers or incumbents, according to the Democratic Legislative Campaign Committee.

More than twice as many Democratic women are running as Republican women—a record 2,374 female Democratic nominees, according to the Rutgers University Center for American Women and Politics—as are four times as many candidates of color. Those Democratic candidates include a remarkable 700 millennials, according to Amanda Litman at Run for Something, the group devoted to encouraging and mentoring young people to run for office, which put a particular emphasis on state legislative races this year.

The once-lackluster DLCC has had three record months of fund-raising, for a total of $35 million so far, and even progressive grassroots groups that criticized the official party arm last year say it’s done a better job helping more candidates run competitive races than in years past, with a beefed-up field program, not just new fundraising prowess. Executive Director Jessica Post announced Sunday that its candidates, staff, and volunteers had knocked a record 1 million doors on Saturday — for a total of 15 million this cycle. The pro-choice Democratic women’s PAC Emily’s List, a federal office–focused group that was challenged by the number of women who came forward to run for these state offices after Donald Trump’s election, has endorsed more than 451 women for state legislative offices this year and contributed nearly $2.3 million either directly to these candidates or to independent expenditure groups working for them. Roughly 20 Emily’s List staff and consultants are focused purely on state and local races across the country, quadrupling the number of staff focused on state and local races in 2016.

Forward Majority, the group founded last year to work on statehouse races where the legislature controls redistricting, is investing $9 million in 120 districts across six states, Texas, Florida, Wisconsin, Pennsylvania, Michigan, and Arizona. The group makes sure its candidates can run a fully funded digital and mail program.

Daily Kos has raised almost $900,000 for state races this year; it recently launched a new campaign for women running in Florida, Wisconsin, Michigan, North Carolina, and Pennsylvania, and raised $307,000 in three weeks. A newish group called EveryDistrict has raised almost $400,000 for 62 candidates across Arizona, Florida, Michigan, Ohio, and Pennsylvania. Future Now, which organizes supporters to create “giving circles” to involve their friends in fundraising, is supporting more than 60 candidates in Maine, New Hampshire, Michigan, North Carolina and Arizona. Flippable, which raised money to support five winning candidates in Virginia last year, is now working to flip 14 legislative chambers in 10 states. And in just over a month, Data for Progress’s “Give Smart” program raised $850,000 online for 14 progressive state candidates, most of them women.

Yet Democrats still lag badly behind Republicans in fund-raising at the state legislative level. It’s not fatal—most Virginia Democrats won despite being out spent—but some groups hoped more big Democratic donors would see the statehouse opportunities, and they did not. There is still no “Operation Bluemap” backed and funded by the top tier of Democratic donors and strategists. Still, Christine Bachman of The People PAC, who was widely credited with helping get Virginia Democrats national funding and attention in 2017, is optimistic about the prospects for Tuesday.

“It’s a different culture now,” Bachman told me on Sunday, after her group, which focuses on getting filmmakers and other “creatives” to contribute time to state candidates’ commercials and social-media presence, helped make 83 videos for candidates in six states. “That narrow mindset a lot of people had about the Virginia races last year—‘oh, maybe we can flip five seats?’—that’s gone. We have a lot of people in a lot of states who want to expand the map.”

A survey of groups and activists working at the state legislative level shows a range of projections of how many seats Democrats might gain and how many legislative bodies they might flip. Nobody expects Democrats to lose seats or chambers, which has to be acknowledged as a win in itself. EveryDistrict, a data-driven group that looks at seats held by Republicans that were either won by Hillary Clinton or lost by less than five points, plus whether Democratic challengers have raised enough money and run a good enough field operation to make them “viable” (not an exactly scientific term), is the most optimistic, projecting Democrats could win 496 seats, and flip 14 state chambers, if there’s a big blue-voter wave.

The DLCC is more modest, believing the party can pick up between 300 and 350 seats and flip as many as eight chambers. Carolyn Fiddler at Daily Kos, one of the most respected wizards of state legislative politics in the country, thinks Democrats can pick up five to eight chambers. When I remind her she told me she thought Democrats could win five to eight seats in Virginia, and they won 15, she chuckled. That’s just coincidence, she said. She also admitted that she’s conservative in her assessments. “I hope to be that level of wrong again.”

Of course, in the event of a big blue wave, all bets are off and all things are possible. But the fundamental truth is that waves have to be built, and campaigners are optimistic that in many states, the infrastructure to carry a wave forward is there. To the extent that Democrats have made the wave bigger, it’s by running a record number of candidates. And there are also a record number of groups, though not enough, who are trying to help good candidates who are running in tough races.

“We’re trying to ensure in the event of a wave that Democrats have a fighting chance at actually flipping legislatures in states most critical for redistricting and in 2020, rather than just make incremental gains,” says Ben Wexler-Waite of Forward Majority. Chris Bachman agrees: “If we had a 90 percent success rate, that would be a failure for us. We’re trying to help candidates who need real help.”

There’s a fair amount of agreement about where Democrats have the best chance of flipping chambers (though nothing is certain). People I talked to seemed to agree that the Democrats are in good shape to take the state senates in Maine, New York, and Colorado, and flip the New Hampshire House. In the next tier, there’s growing optimism about taking back the House in Iowa and Minnesota and the Senate in Arizona. After that, opinions diverge, but some smart activists also think Democrats can win the Michigan House and the Florida and Wisconsin senates.

After that, it’s dicier. Forward Majority is working hard in Pennsylvania and Texas; taking back either is tough, but Wexler-Waite says Democrats haven’t had such good candidates in either state for many years. Bachman’s group is working hard on ending the Republican supermajority in the North Carolina House, and she believes, again in the event of that legendary blue wave, Dems could take that statehouse too.

All of the groups involved in state races say their work will continue in 2020—and in Virginia, in 2019, where the House of Delegates seats are up again. Most of the Democrats who lost close races there in 2017 are running again, and Chris Bachman and others are already preparing to support them. But 2020 may be a tougher environment, paradoxically: Although the presidential race is likely to boost voter turnout, it will make fund-raising even tougher. “The presidential race is already occupying a large portion of every conversation we have,” says Drew Morrison of EveryDistrict. “But our model makes fund-raising an organizing opportunity, and makes sure everybody’s engaged in their local community,” which may keep them from being totally distracted by the shiny lure of Democratic primaries, he said.

In many ways, 2020 is the ultimate test of this state-level activism, because the next year, the 37 state legislatures that control redistricting in Congress and in their own states begin the process again. If Democrats pick up eight state chambers on Tuesday, in two years they will have another shot at picking up more, in a year when Democrats’ turnout normally surges. “Republicans have used state governments as a staging ground to wage the greatest assault on Americans’ right to vote since the civil-rights Era and rig Congress to the point where nearly the entire GOP House majority can be attributed to gerrymandering,” says Forward Majority’s Ben Wexler-Waite. If Democrats do well on Tuesday, it will be easier to complete the job in 2020, and rescue democracy a decade after Republicans took it hostage.