Groups gather for the Women’s March on Washington on Jan. 21. The campaign arm for House Democrats is hiring organizers in 20 key districts to harness grass-roots outrage against President Trump to elect Democrats in 2018. (Amanda Voisard/For The Washington Post)

Democrats are moving urgently to harness the wave of grass-roots protests that have greeted President Trump in his first weeks in office to reclaim the House majority in next year’s midterm elections.

As of this week, the Democratic Congressional Campaign Committee is hiring full-time operatives to do political organizing work in 20 key Republican-held districts — an unusually early investment in House races that do not even have declared candidates yet.

Rep. Ben Ray Luján (D-N.M.), the committee’s chairman, called the move “unprecedented” for Democrats, who need to pick up two dozen GOP-held seats to win the majority.

“We’ve seen women and people gather around America to march for progress; now we’re asking them to run for office, to volunteer and to vote,” he said. “I can very safely say that the DCCC has never done this this early, and I don’t know of any other of the campaign committees that have launched an initiative like this this early.”

The “March Into ’18” effort comes after consecutive weekends of large-scale protests nationwide targeting Trump and his policies.

On Jan. 21, a day after Trump’s inauguration, more than 1 million gathered in Washington and cities across the country to rebuke Trump’s policies and remarks about women, minorities and immigrants. Last weekend, thousands more protested Trump’s executive order temporarily halting refu­gee admittance and barring citizens of seven Muslim-majority countries from entering the United States.

Luján also pointed to smaller-scale protests that have sprung up against GOP plans to repeal the Affordable Care Act — such as a constituent event held last month in a Denver suburb that ended with Rep. Mike Coffman (R-Colo.) leaving through a back door.

None of the protests were formally organized by Democrats, but Democratic officials have fervently embraced the activism. On Saturday, for instance, numerous elected officials and candidates for Democratic National Committee leadership posts went to airports around the country to join in protests against the travel ban.

The DCCC’s organizing push is aimed at turning that activism into votes come November 2018. The new field operatives, Luján said, will be hired in most cases from within the targeted districts and who have previously worked on House campaigns there.

“We were able to quickly reach out to people we have trained as organizers, that have already been on campaigns, that know the communities and leaders, that know many of these districts,” he said. “We’re bringing them right back into the fold.”

A person familiar with the committee’s plans said the operatives will develop relationships and coordinate with local grass-roots leaders who are already taking part in protests and work with them to build capacity — teaching them, for instance, how to set up phone banks, write letters to newspapers, organize rallies and meetups, and use social media to promote events and share photos and video.

A “March Into ’18” website featuring a photo of the Jan. 21 Women’s March on Washington invites voters to sign up and get information on local events — such as lawmakers’ town hall meetings. The DCCC is also placing Twitter ads targeting people who have followed or shared information about protests and events in the targeted districts.

The 20 targets include many of the districts where Democrats hoped to unseat Republicans last year — including suburban districts in California, Minnesota, Pennsylvania and Colorado. But they are also going into districts represented by veteran GOP lawmakers — such as Reps. John Abney Culberson (Tex.), Peter J. Roskam (Ill.), Edward R. Royce (Calif.) and Pete Sessions (Tex.) — who did not face a strong 2016 challenge but where Democratic presidential nominee Hillary Clinton ended up beating Trump.

Democrats fell short of aggressive expectations last year, picking up six seats after leaders including House Minority Leader Nancy Pelosi (D-Calif.) spoke openly of gaining the 30 seats necessary to oust Republicans from the majority.

Republicans are aware of the head winds they will probably face: They underwent a midterm reversal of their own in 2006, when Democrats won the majority and Pelosi became House speaker.

Rep. Tom Cole (R-Okla.) — a former chairman of the National Republican Congressional Committee, the DCCC’s counterpart — said the GOP still had demographic and geographic advantages to rely on. But he said the mood of the electorate will matter most.

“Nobody’s had a good off-year election since 2006, whether it was us or them,” he said. “When you do things, you create opposition, so it’s going to be a much tougher environment.”

Looking toward 2018, Democrats are hoping to avoid the dip in voter engagement they saw in the past two midterms under President Barack Obama, through which Republicans were able to build their strongest House majority since 1930. Major elements of the traditional Democratic coalition — younger, poorer and minority voters — simply did not turn out as strongly as they did in presidential election years.

Luján acknowledged that will have to change if Democrats can expect to retake the majority in two years: “A big part of this initiative is to help educate voters and create more awareness of the importance of midterm elections, and to stay just as active in a midterm election as you would in a presidential election.”