(Reuters) - Democrats claimed historic gains in Virginia’s statehouse and booted Republicans from state and local office across the United States on Tuesday, in the party’s first big wave of victories since Republican Donald Trump’s won the White House a year ago.

Democrats must figure out how to turn that momentum to their advantage in November 2018 elections, when control of the U.S. Congress and scores of statehouses will be at stake.

From coast to coast, Democratic victories showed grassroots resistance to Trump rallying the party’s base, while independent and conservative voters appeared frustrated with the unpopular Republican leadership in Washington.

Democrats won this year’s races for governor in Virginia and New Jersey, but successes in legislative and local races nationwide may have revealed more about where the party stands a year into Trump’s administration.

Unexpectedly massive Democratic gains in Virginia’s statehouse surprised even the most optimistic party loyalists in a state that has trended Democratic in recent years but remains a top target for both parties in national elections.

“This is beyond our wildest expectations, to be honest,” said Catherine Vaughan, co-founder of Flippable, one of several new startup progressive groups rebuilding the party at the grassroots level.

With several races still too close to call, Democrats were close to flipping, or splitting, control of the Virginia House of Delegates, erasing overnight a two-to-one Republican majority.

Democratic Lieutenant Governor Ralph Northam also defeated Republican Ed Gillespie by nearly nine percentage points in what had seemed a closer contest for Virginia’s governor’s mansion, a year after Democrat Hillary Clinton carried the state by five points in the presidential election.

The losing candidate had employed Trump-style campaign tactics that highlighted divisive issues such as immigration, although the president did not join him on the campaign trail.

In New Jersey, a Democratic presidential stronghold, voters replaced a two-term Republican governor with a Democrat and increased the party’s majorities in the state legislature.

Democrats notched additional wins in a Washington state Senate race that gave the party full control of the state government and in Republican-controlled Georgia, where Democrats picked up three seats in special state legislative elections.

‘A MESSAGE’ TO TRUMP

“This was the first chance that the voters got to send a message to Donald Trump and they took advantage of it,” John Feehery, a Republican strategist in Washington, said by phone.

FILE PHOTO: Democratic candidate Phil Murphy celebrates with his running mate, Lieutenant Governor-elect Sheila Oliver, after he was elected Governor of New Jersey, in Asbury Park, New Jersey, U.S., November 7, 2017. REUTERS/Lucas Jackson/File Photo

The gains suggested to some election analysts that Democrats could retake the U.S. House of Representatives next year. Republicans control both the House and Senate along with the White House.

Dave Wasserman, who analyzes U.S. House and statehouse races for the nonpartisan Cook Political Report, called the Virginia results a “tidal wave.”

Even after Tuesday’s gains, however, Democrats are completely locked out of power in 26 state governments. Republicans control two-thirds of U.S. legislative chambers.

Desperate to rebuild, national Democrats this year showed newfound interest in legislative contests and races even farther down the ballot. The Democratic National Committee successfully invested in mayoral races from St. Petersburg, Florida, to Manchester, New Hampshire.

“If there is a lesson to be taken from yesterday, it is that we need to make sure that we are competing everywhere, because Democrats can win,” DNC Chairman Tom Perez said on a media call.

Democratic Legislative Campaign Committee executive director Jessica Post said national party leaders must remain focused on local races, even in a congressional year.

“We don’t focus enough on the state level, and that is why we are in the place we are,” she said. “But when we do, we win.”