In the general election, she ran for re-election against Democratic State Senator Jennifer Wexton in what was considered one of the most competitive House races, given that Clinton and Governor Ralph Northam easily won her district in 2016 and 2017, respectively. Additionally Democrats made significant gains in Northern Virginia in the 2017 elections, resulting in Comstock being the only elected Republican above the county level in much of the district. In the November 2018 general election, Comstock was defeated by Wexton, who took 56% of the vote to Comstock's 44%. Comstock had been the only Republican to represent a congressional district based in the Washington suburbs.