Virginia 10th Congressional District Democratic nominee state Sen. Jennifer Wexton (Loudoun) and Rep. Barbara Comstock (R) debate on Sept. 21 in Leesburg. (Pete Marovich/For The Washington Post)

Mark J. Rozell is dean of the Schar School of Policy and Government at George Mason University.

Is Rep. Barbara Comstock doomed to defeat, as several polls suggest? Is the Trump factor in this election cycle too much of a drag on any incumbent Republican, especially one running in Virginia’s 10th Congressional District?

Conventional political wisdom regarding midterm House races is that they are largely about local issues and personalities and that national trends have at most a marginal overall impact on each district. Incumbents possess all of the advantages — name identification, resources and a legislative record — while challengers are left hoping for some larger national force to upend the typical campaign dynamics of House races.

In any normal election cycle, it would be a safe bet that Comstock would be riding the powers of incumbency to an easy reelection. Two years ago, even when the top of the GOP ticket got trounced in her district, Comstock won by a comfortable six-point margin. Voters in Virginia’s 10th District apparently are not adverse to split-ticket voting.

This year, President Trump is not on the ballot, and the latest Post-Schar School poll shows 84 percent of district likely voters rate the economy positively. So logic would suggest an easy reelection year for the incumbent.

But it is as though Trump alone is on the ballot this year, and that is the major problem for Comstock. In 2016, when most considered a Trump victory unlikely, district voters felt safe splitting their ticket and sticking with the incumbent Comstock. She had won praises and high-profile editorial endorsements for her service in the House, so why change?

But everything is changed this year. In The Post-Schar School poll of the district, one third of Comstock’s constituents selected Trump as the most important motivating factor in their voting decision. Although Comstock has tried to separate herself from the president, it appears that many of her constituents are simply in an angry mood about this president and are looking for a vehicle to express that. Going after the incumbent of the president’s party is their only weapon this year.

The district poll reveals what is common around the country right now: Partisans on each side — more than 90 percent in Virginia’s 10th — have lined up solidly for the candidates of their own parties. The trouble for Comstock is that there are not enough Republicans in that district to carry her, so she needs to win independent voters.

And that is where Comstock’s chances appear to fall apart. Self-identified independents prefer Jennifer Wexton, the Democratic nominee, over Comstock by a whopping 60 to 36 percent. Additionally, about one-third of the district’s households report a family member who is connected to federal government work (government employee, contractor, lobbyist or consultant). The president’s anti-government “drain the swamp” message may play well outside of Washington, but it sure doesn’t sit well here.

There is nothing in the survey data to suggest any ray of light for Comstock, although a highly vulnerable incumbent can sometimes overcome a very weak challenger. That leaves the Wexton factor in this race.

Voters are not lighting up with enthusiasm for Wexton. Her favorability rating is a mere 44 percent, with 25 percent having no opinion of her or being entirely unfamiliar, although a 55 percent majority of those say they would vote for her if the election were held today. It appears that in this anti-Trump environment in the district, merely put a credible person with a D next to her or his name and it’s probably game over right there.

In the remaining weeks of the election cycle therefore, Comstock has to hope that voters ultimately put their support behind a known incumbent over a lesser known challenger. In any typical midterm, the hard-working, diligent constituency-services-focused incumbent — with no whiff of scandal and who in prior elections won endorsements even from unlikely sources — would be an easy reelect.

There is nothing typical this election year. The survey data make it clear: It’s all about Trump.