Virginia's 10th congressional district election was one of the highest-profile United States House of Representatives elections of 2018, and the most competitive in Virginia. Republican incumbent Barbara Comstock lost re-election to a third term to Democrat Jennifer Wexton, a lawyer and state senator representing Loudoun County.

In the general election, held on November 6, 2018, the race was called relatively early in the night, with Wexton finishing with 56 percent of the vote to Comstock's 44 percent. Wexton's victory was described as illustrative of a "blue wave" in which Democrats won back the House majority that year and made gains in other offices across the country and as a repudiation of then-President Trump.

Comstock's loss was blamed on her association with then-President Trump, even as she emphasized her independence from him. Former state legislator David Ramadan, who is close to Comstock, blamed Trump for her loss, saying, "There's no other way to put it but that this is the fault of the moron in the White House." In preliminary results from a Washington Post-Schar School survey of voters in the 10th District, about 6 in 10 voters said Trump was one of the two most important factors in their vote.

Virginia's 10th District was one of the most expensive House races in the United States, with both campaigns spending a total of $11 million.

Comstock's loss meant that until the next voting cycle no Republicans would be representing the immediate Washington region. In the June 12, 2018 Republican primary election, Comstock defeated her rival, Air Force veteran Shak Hill. In the Democratic primary, Wexton defeated scientist Julia Biggins, former State Department official Alison Friedman, Army veteran Dan Helmer, former Department of Veterans Affairs official Lindsey Davis Stover, and former federal prosecutor Paul Pelletier.

Background Virginia's 10th congressional district has a higher median income than any other congressional district outside of Silicon Valley. The district is home to the Central Intelligence Agency and many of the country's biggest defense companies, IT firms, and government contractors. The 10th covers McLean and Manassas, and then stretches west from Loudoun to the West Virginia line. The 10th district is the most college-educated GOP-held district in the country, and 37 percent of its residents are non-white. Only five congressional districts have more federal workers than the 10th, and all are within Virginia, Maryland or the District.

Ever since 17-term Republican Rep. Frank Wolf's retirement, Democrats had seen the 10th district as ripe for a challenge, but Comstock had won by solid margins since her first run in 2014, when she rode a solid advantage in fundraising to the victory over Fairfax County supervisor John Foust. In 2016, Comstock's challenger, Democrat LuAnn Bennett, became the first 10th District Democrat to win in Loudoun since 1978, but Comstock still won with 210,791 (52.7 percent) to Bennett's 187,712 votes (46.9 percent) of the ballots cast. The 10th district is one of 23 districts across the country that split their ticket in 2016 by voting for Democrat Hillary Clinton for president and a Republican for representative.

Virginia was one of at least 13 congressional races in 2018 in which the Democratic challenger raised over $1 million in the second quarter. VCU politics professor Ravi Perry points out that Comstock's fundraising edge was in contrast to the situation in Virginia's 2nd, 5th, and 7th districts, where Democrats out-fundraised their opponents in the second quarter: "They're aware of the swing district nature of it, and are clearly investing in it accordingly."

After 2018 Ohio's 12th congressional district special election, Fox commentator Chad Pergram noted that like Virginia's 10th district, Ohio's 12th congressional district had suburban areas (Franklin County, Ohio) where Democrats dominated and rural areas (Delaware County, Ohio) where they did not: "Democrats need to extend their reach to the distant suburbs in order to get somewhere this fall." In the rural parts of the 10th district, there was some concern that the 2018 China–United States trade war and the Trump tariffs on steel and aluminum, along with anti-immigrant rhetoric and policies that make it harder to find migrant workers, could reduce the profitability of agricultural businesses. According to Mark Rozell, dean of George Mason University's Schar School of Policy and Government, "They may think Comstock has done a good job, she has represented the district well, she does great constituent services, she shows up everywhere to every local event, and for some of these voters none of that matters. The bigger issue is sending that message about the current direction of the Trump administration."

National significance Democrats had to pick up at least an additional 24 seats in the 2018 House elections to win back the majority they lost in the 2010 election. This effort was focused on defending Democratic seats while picking up Republican seats, especially in races that were tossups or where the districts leaned Democratic. In a "blue wave" election, which saw Democrats win back the House majority and make significant gains in other offices across the country, many Republican incumbents were voted out, Republican politicians retired in record numbers, but Comstock had opted to fight for her seat. Democratic Rep. Don Beyer said that in Virginia, Comstock would be "the No. 1 target – we're going to put everyone behind it."

Comstock had been described, by the numbers, as arguably the most vulnerable Republican House member. This was partly because northern Virginia has become increasingly Democratic. In the 2017 Virginia House of Delegates election, seven of the eight Republican incumbents in the state legislature with districts touching Comstock's were defeated by Democrats. Among other reasons for Democrats' optimism about winning the election were that Democrat Hillary Clinton defeated Republican Donald Trump by 10 points in the 10th district in the 2016 United States presidential election, and Democrat Ralph Northam won in the 10th district by a 13 percent margin in the 2017 Virginia gubernatorial election. Democrats believed Comstock would be defeated by Democratic voters bent on defeating anyone who shared a party affiliation with Trump.

Comstock, however, won by 6 points in 2016, despite the Republican presidential ticket's loss in her district. She had said that the 2017 election results did not change her plans for the 2018 election, because in her view, listening to the voters of the district and focusing on the district's priorities were what were important. In addition to the fact that Comstock was at first a proven winner in districts bluer than the national average, another challenge Democrats faced in unseating her was that the D.C. media market was one of the most expensive in the country, and reached many people who did not live in the district. This made it necessary to raise large amounts of money, including from outside groups.

Wasserman noted that "several Republicans privately express doubts about spending millions on expensive DC television trying to save this seat when there are far cheaper routes to holding the majority." According to Washington Post reporter Jenna Portnoy, in April 2018, "Experts say Comstock will be tough to beat given her strong name recognition, relentless campaign style and embrace of some moderate positions that polls show resonate with voters in the closest thing Virginia has to a swing district." Comstock is also renowned for her political smarts.

According to Comstock's political director Ken Nunnenkamp, "Democrats have spent over $20 million trying to defeat her and they have a 0-5 record to show for it," and he cautioned against underestimating her. He said, "Those failed campaigns have also had one thing in common – the bitter partisan advice of Kathleen Murphy," who lost a 2013 House of Delegates race to Comstock and then won a 2015 special election after Comstock resigned.

For the second election cycle in a row, Comstock was on the National Republican Congressional Committee Patriot Program list of vulnerable House members who would receive additional financial and strategic support for their races. The NRCC made its largest reservation for television advertising time, $6.4 million, for Comstock in the expensive Washington media market. The race was expected to be one of the most competitive, and costly, congressional races nationwide.

The Wall Street Journal noted that then-President Trump, by threatening a government shutdown, could be purposefully putting Republican House members like Comstock at risk of defeat, so that in the 2020 United States presidential election, he could use Democratic House Speaker Nancy Pelosi as a foil.

According to Jake Kastan, although the party that controls the White House typically loses, on average, 32 seats in the first midterm election, Republican incumbents like Comstock had many advantages, including more money and resilient local brands. He drew several distinctions between the 2018 election and the 2010 Republican wave election, noting that 57 percent of Americans said things are going well in the U.S. today, the largest proportion to share these sentiments since January 2007. He also noted that House Republicans had unveiled a "Better Off Now" message that makes the connection between GOP policies and record low unemployment, a surging economy, higher take-home pay, and a strengthened military. And he pointed out that even if Republican incumbents like Comstock did lose, it may not win Democrats the House, since Republicans were said to be favored in many districts with open seats, and there were only nine Republicans in the House representing districts that tilt Democratic.

Primaries As of April, Comstock had posted one of the largest fundraising hauls of the first quarter of 2018, and four separate Democrats in the district had posted fundraising hauls of more than $200,000. The fact that the field of six Democrats raised more than $4.4 million combined for the Democratic primary was seen as a sign of Democratic enthusiasm. The 10th district race also drew in the most money in the state in the second quarter.

As of May 2018, ahead of primary voting, Roll Call listed Comstock as one of only three incumbents running in districts rated as tossups. After the primary election, the Cook Political Report moved the district (along with four other districts) from "Toss Up" to "Lean Democratic," noting Comstock's underwhelming performance against Hill, including in the Shenandoah Valley, and the possibility that Republican senatorial candidate Corey Stewart's nomination could "alienate independents, depress Republican interest in the Senate race and allow Kaine to run up the score in the 10th CD, compounding Comstock's challenge." In particular, Stewart's stances on Confederate monuments and immigration may have lowered turnout among educated suburban Republicans.

The University of Virginia Center for Politics made a similar assessment. According to Mark J. Rozell, it seems likely that Comstock's appeals to mainstream and independent voters would be overshadowed by Trump's and Stewart's louder rhetoric directed to the hard-core right wing. A study by the Christopher Newport University Wason Center for Civic Leadership's Rachel Bitecofer predicted Comstock would lose and that the deciding factor for Democrats was getting their own partisans to the polls rather than swaying independent voters. Comstock herself had said, "We're up in our internal polls, and I have never underperformed my internal polls."

Democratic

Candidates Julia Biggins