Democrat Daniel Helmer, shown in the back yard of his Fairfax County home, announced his congressional campaign on April 11. (Marvin Joseph/The Washington Post)

Democrat Daniel Helmer, an Army veteran and Rhodes Scholar emboldened by the election of President Trump, on Tuesday announced his campaign to challenge Rep. Barbara Comstock (R-Va.).

Helmer said he has raised $120,000 — an amount he hopes will set him apart from a crowded field of candidates that is shaping up ahead of the 2018 midterm elections.

“This election evidences a loss of trust between our people and our government and a desire for new leadership and fresh perspectives,” he said Monday afternoon as his family’s cocker spaniel and English bull terrier padded around the patio of his Fairfax County home. “It’s important for America that we fix this.”

As the closest thing to a swing district in the Washington metro area, the Northern Virginia district is experiencing a surge in liberal activism. Political newcomers are registering in large numbers to challenge GOP lawmakers in state House districts that went to Hillary Clinton in the presidential race.

Helmer’s announcement came on the same day that three other military veterans kicked off campaigns to try to unseat Republican incumbents in California, Colorado and Pennsylvania.

Rep. Barbara Comstock (R-Va.) celebrates her election victory in 2016. (J. Lawler Duggan/For The Washington Post)

On Monday, a political action committee called Take Back the Tenth erected a billboard near Winchester urging Comstock to hold a town hall.

Members of the Indivisible VA District 10 Facebook group are planning daily demonstrations outside Comstock’s Sterling district office this week while Congress is in recess. Each day they will focus on a different issue, such as climate change, immigration, health care and Russian interference in the 2016 election.

Comstock is part of a House delegation spending the week in the Middle East and was celebrating Palm Sunday Mass with U.S. troops on the Sinai Peninsula at the time of the deadly bombings in Egypt, said her spokesman, Jeff Marschner. (The U.S. military organized the trip at taxpayers’ expense.)

Comstock won a second term by six percentage points in November, despite independent analysts’ predictions that the race would be a squeaker. Nationally, Democrats and Republicans poured resources into the district, and outside groups spent about $15 million there.

Democrats think they have a chance to unseat Comstock because Clinton won the district by double digits and, they say, Trump is unpopular with the affluent, diverse and highly educated population of Loudoun County, the heart of the district.

Comstock, however, remains popular. She raised more than $500,000 in the first quarter of the year, according to her campaign. Complete reports are due Saturday.

Helmer, 35, kicked off his campaign with a day-long tour of businesses throughout the district. He also planned to donate blood and knock on some doors. The sprawling district includes moderate suburbs outside the District and conservative strongholds near the West Virginia border.

He lives in the Springfield section of Fairfax County. Echoing results across the congressional district, Clinton carried his voting precinct by six percentage points last year, but Comstock won it by 11 points.

Like Comstock, Helmer denounced Trump’s freeze on federal hires and the sweeping cuts in his budget proposal.

“This district is made up of many dedicated public servants who are seeing the potential to have their jobs undermined by what’s coming,” he said.

A New Jersey native, Helmer moved to the district with his wife and two sons in December 2013, about the time the Army major was released from active duty. He serves in the reserves and works as a strategic adviser at the Boston Consulting Group, he said.

The grandson of Holocaust survivors, Helmer graduated from the U.S. Military Academy and was deployed to Iraq in 2004. As the only Arabic speaker in his battalion, he served as an assistant intelligence officer before studying international relations at Oxford University on a Rhodes scholarship.

In 2007, while stationed in Afghanistan, the commanding general summoned him to Kabul to give a presentation on counterinsurgency training, he said. His advice to bring Afghan and coalition leaders together to work on problems was implemented within six weeks, he said.

Helmer, who has hired media and polling consultants and has one staffer on the payroll so far, is the second Democratic candidate to announce their intentions.

The other is Kimberly Adams, the immediate past president of the Fairfax County Education Association and current president of the Fairfax County Council of PTAs. As of Monday afternoon, she had raised $4,670 through Crowdpac, an online fundraising tool.

State Sen. Jennifer T. Wexton, a lawyer from Loudoun County, and Lindsey Davis Stover, a communications strategist from McLean who served in the Obama administration, have met with Democratic groups and are considering running.

Also thinking about jumping into the Democratic race are Dorothy McAuliffe, the wife of Virginia Gov. Terry McAuliffe; Fairfax County Supervisor Kathy L. Smith; Fairfax County School Board member Ryan McElveen; and Jimmy Bierman, a lawyer from McLean.

More than a year ahead of the contest, the field is likely to remain in flux for months.