It’s unclear how Rose’s public support for the impeachment inquiry, and his vote on the rules resolution, could affect his reelection, but Trump is popular in the 11th District, which includes Staten Island and a sliver of Brooklyn. GOP leadership has signaled that Assemblywoman Nicole Malliotakis is their preferred candidate. She carried the 11th District when she ran unsuccessfully for New York mayor in 2017. It’s still unclear, though, whether former GOP Rep. Michael G. Grimm, who served prison time for tax fraud, will jump in the race. Rose has continued to build his war chest, raising nearly $735,000 in the third quarter compared to Malliotakis’ $206,000.

McAdams is the only Democrat in Congress representing heavily Republican Utah. His name recognition and popularity at home — he is the former mayor of Salt Lake County — helped him unseat two-term GOP Rep. Mia Love in 2018. But a growing field of Republicans will be vying for the chance to challenge him, including state Sen. Dan Hemmert, who has ties to the popular Republican Sen. Mitt Romney.

Of the 43 seats Democrats flipped in 2018, Brindisi’s backed Trump by the highest margin two years earlier. Republicans believe Trump’s presence on the 2020 ballot will bring out his supporters in this upstate New York district who stayed home in 2018, dooming Brindisi. But Democrats believe the incumbent’s strength in fundraising, name recognition and his tendency to break with his party — he was long a holdout on backing the impeachment inquiry before voting in favor of the rules measure — could make him tough to beat. Brindisi could face a rematch with the Republican he unseated, Claudia Tenney, who has been known to make controversial comments.

Trump’s large margin of victory in 2016, and Torres Small’s narrow win two years later, puts this New Mexico seat in the GOP’s sights. But Democrats say Torres Small, a water rights lawyer whose campaign videos showed off her rifle skills, is a perfect fit for the rural district. There’s a good chance the 2020 election will be a rematch with her 2018 rival, former state Rep. Yvette Herrell, who has rebuilt her campaign team. Republicans are also excited about Claire Chase, the former chairwoman of the New Mexico Oil and Gas Association. It’s unclear, though, how Chase’s record as a onetime Trump critic will play in a GOP primary, especially after publicity over a 2015 Facebook post in which she used an expletive and said Trump was “unworthy of the office.”

The chairman of the Agriculture Committee is widely regarded as the last Democrat who can hold on to this sprawling, rural district. Peterson is one of the most conservative Democrats in the House — he’s voted with Trump more than any other Democrat, according to CQ Vote Watch, and he was one of just two Democrats to vote against the impeachment inquiry rules resolution — but that might not be enough to save him. He only narrowly defeated an underfunded GOP challenger the past two cycles, but in 2020, he’s likely to face a much stronger opponent in former Minnesota Lt. Gov. Michelle Fischbach, a recruit national Republicans are excited about.