A composite image, clockwise from top left, of Democrats Danica Roem, Andrew A. Adams, Mansimran Kahlon and Steven Jansen. The four candidates are competing in the June 13 Democratic primary for the chance to challenge Republican Del. Robert G. Marshall in the November general election. (J. Lawler Duggan/For The Washington Post)

Outspoken and often far-right enough to bewilder even some of his fellow Virginia Republicans, Del. Robert G. Marshall has been a constant target of aggressive Democratic challenges since he first won his Prince William County district in 1992.

This year, amid a massive push by Democrats to ride anti-Donald Trump sentiments to victory in Richmond, the 73-year-old legislator known for such pronouncements as calling disabled children God’s punishment on women who have had abortions may be heading for his toughest fight yet.

Vying for a chance to take him out during next week’s Democratic primary election are a transgender ex-journalist, a religious Sikh businessman and two moderate white professionals — four candidates who reflect how much Northern Virginia has changed during Marshall’s 13 terms in office.

“This year looks very different than previous election cycles,” said Stephen J. Farnsworth, a ­political-science professor at the University of Mary Washington in Fredericksburg.

“What you see in Prince William County generally, and in this district in particular, is a growing diversity, and that growing diversity is not an ally of a Republican candidate,” Farnsworth said. “The unpopularity of Trump may be creating an environment where a lot of Democrats are more motivated this fall than they were two or four years ago.”

Del. Robert G. Marshall (R-Prince William) gestures during a committee hearing at the Capitol in Richmond on Jan. 19. The committee voted down his transgender bathroom bill. (Steve Helber/AP)

A fixture in Richmond with avuncular charm, Marshall has held on to his once solidly conservative district — which includes a portion of Manassas — with a bread-and-butter approach to constituent services and a candid demeanor admired by many voters.

But those victories are often overshadowed by Marshall’s fights against his own party leaders and public pronouncements that place him squarely on the conservative fringe.

Besides calling disabled children a punishment for abortions, Marshall has suggested that incest is sometimes “voluntary” and, most recently, argued that allowing transgender women to use a ladies’ restroom is an opening for sexual predators.

The four candidates hoping to be the Democrat to take him on in November have been casting the Republican incumbent as an out-of-touch ideologue while canvassing for votes in communities lined with brick rambler houses or towering McMansions.

In recent years, the 13th District has turned purple and become a battleground between the parties. In his 2013 bid for governor, Terry McAuliffe (D) squeaked to victory in the district by one percentage point. The following year, Republican Ed Gillespie — now the front-runner in his party’s gubernatorial primary race — took 51 percent of the district in his failed campaign for the U.S. Senate against Mark R. Warner (D-Va.). Democrats running in presidential contests have an easier time — Hillary Clinton won 54 percent of the vote in the district last fall, and Barack Obama carried it in 2008 and in 2012.

In the delegate primary, the four candidates have highlighted the area’s increasingly pressing problems with traffic congestion, overcrowded schools and stagnant retail strips — calling Marshall ineffective in dealing with them.

Danica Roem, a former Gainesville and Prince William Times reporter, has used her stature as a transgender candidate to criticize Marshall’s conservative stances — including a now-tabled “bathroom bill” he sponsored earlier this year that would have required people to use restrooms assigned to their original sex.

“Bob Marshall is more concerned about where I use the bathroom than how to get people to work,” Roem, 32, told one voter in Manassas before launching into a discourse on how to relieve traffic congestion along Route 28.

“For me, this is personal,” said Roem, who would be the first transgender member of the House of Delegates.

Steven Jansen, a former ­Detroit-area county prosecutor who now directs a national nonprofit group based in Alexandria that advocates for better gun-
control laws, is campaigning as a “law-and-order” candidate who appeals to the district’s more moderate Republican voters.

“I’m going to actually take votes away from Bob; that’s how we’re going to win,” Jansen, 43, declared during a recent candidate’s forum. “I’m going to take moderate Republican votes.”

Andrew Adams, 29, a former Army commander who now works as an operations manager for a global pest-control company, argues that Marshall has been able to stay in office for so long because the district is drawn to include conservative precincts where voters are more active.

He wants the General Assembly to create an independent commission that would redraw state districts and guard against gerrymandering that benefits one party over another.

“I think a lot of the solutions to a lot of the problems we have come from people who are somewhere in the middle, not tied to these really deep ideological fights and really just want to get things done,” Adams said.

Mansimran Kahlon, a Sikh businessman in Gainesville, said he was inspired to run for office after a lifetime of living as “the other” in the district he has known since his family arrived in the Prince William area from India when he was age 3 — alienation that he says Marshall has fueled.

His campaign has tapped into the area’s growing South Asian community, so far raising $94,125. Jansen has raised the most with $107,534, Roem has collected $65,854 and Adams has $6,150.

“We have to expand the electorate,” Kahlon, 24, said. “Bob Marshall won’t be beat by going after his own constituents who vote for him time and again. We need to go after those voters who never show up, or who show up in a presidential election but never come out in the state elections.”

Marshall said he is unfazed by the competition.

He won his last election in 2015 by 1,555 votes — against businessman Don Shaw — and other Democrats have tried to take him out in the past.

“I’m not about to change the public policy views I’ve had,” Marshall said, proving so by doubling down on his argument against allowing transgender people to use the bathroom of their choice.

“A boy can’t say: ‘Hey, school administrator, I think I identify as a female today,’ ” Marshall said. “And that’s it; he gets to go into the girls’ shower. That is not going to fly.”

Marshall said the criticisms that he has failed to reduce traffic and resolve other problems are unfounded, and the characterization of him as too conservative is an old tactic that has won no traction with District 13 voters.

“They keep trying this, and I can only hope they’ll keep it up because it hasn’t worked,” he said.

Quentin Kidd, director of Christopher Newport University’s Wason Center for Public Policy in Newport News, Va., said whether that strategy will work this time depends on the voter turnout for the gubernatorial election in November.

Kidd noted that during the 2013 gubernatorial election — when McAuliffe beat former attorney general Ken Cuccinelli in the district by one percentage point — Marshall still prevailed in his election with 498 votes more than Atif Qarni, a Muslim American teacher.

“How big of a victory does the Democrat this year have to have in order to risk Bob Marshall’s reelection?” Kidd said. “One point is not enough.”

Some voters say they are motivated by the national political climate to weigh in locally.

Matt Hale, 33, who lives in Gainesville, said he usually votes Republican but rarely pays attention to what his delegate does.

But he will probably go against Marshall this year, he said.

“I feel like my party kind of just fell apart, and I’m looking for real actual changes,” Hale said. “From what we’ve seen in the general state of affairs, I don’t see myself voting Republican.”