Comstock has proved hard to beat in this affluent, suburban Virginia district that strongly rejected Trump. The former GOP operative has broken with her party on transportation issues that affect federal workers and voted against the Republican health care bill. But Democrats are salivating over her vote for the GOP’s budget blueprint last month, which called for eliminating a deduction for state and local taxes that benefits her constituents. At least three Democrats are raising serious money, and as long as they don’t destroy each other in a primary, one of them could be in a strong position to tie Comstock to Trump and Ryan. The speaker has an even higher disapproval rating than the president in the district, according to an October survey by PPP. Trump handily carried Tenney’s upstate New York district by 16 points, while Tenney won by a smaller 6-point margin in a race that featured a well-funded third party candidate. But the first-term congresswoman could have a formidable challenger who Democrats believe can win in the GOP-leaning district. State Assemblyman Anthony Brindisi, whose state Assembly district overlaps in part with the 22nd, has so far had the primary to himself. Brindisi has also outraised Tenney, bringing in twice as much as her in the third quarter.

O’Halleran defeated a flawed GOP candidate last cycle and is now facing his first re-election. A former Republican state legislator, O’Halleran joined the Blue Dog Caucus in Congress and, so far, has voted with his party less than the average House Democrat, according to CQ’s Vote Watch. Republicans have several candidates running here, and their nominee won’t be decided until late summer next year. But in a district that’s marginally voted Republican at the top of the ticket in recent cycles, O’Halleran is vulnerable as a freshman Democrat.

Nolan’s never had an easy race in his Minnesota district since returning to Congress in 2013. Despite lackluster fundraising, his retail political skills (and outside spending) have helped him hold on. Last fall, he won by just half a point while Trump carried the district by 16 points. This year, Nolan’s efforts to move closer to mining interests in the Iron Range have earned him a long-shot challenger for the Democratic-Farmer-Labor endorsement. After twice defeating wealthy businessman Stewart Mills, who said last week he’s not running, Nolan may face Pete Stauber, a Republican with more authentic ties to the district’s working-class voters. Stauber narrowly outraised Nolan.

Hurd is in a Toss-up race in a swing district that is also the largest in Texas. Clinton carried it by 3 points, and a Democrat won the seat as recently as 2012. Hurd has been touted as a rising star in the GOP, and he was re-elected in 2016 by 1 point. But the broader national environment and the diversity in the district (more than 70 percent of the population is Latino) puts it in play. Though a number of Democrats are vying to take on Hurd, some Democrats believe they could have a better chance with a new name. The previous holder, Democrat Pete Gallego, lost to Hurd in 2014 and a rematch last year.