As for those getting out in 2018, Trump’s low approval rating and Congress’s meager legislative output may be contributing to the decisions of some Republicans to retire, including moderate Representatives Ileana Ros-Lehtinen of Florida, Charlie Dent of Pennsylvania, Rodney Frelinghuysen and Frank LoBiondo of New Jersey, and Dave Reichert of Washington state. But there are other factors at play. Unlike Democrats, Republicans have rules limiting the terms of their committee chairmen to ensure turnover and give younger members a chance to advance in the House. Congress isn’t as fun with less power, and six of the departing GOP committee leaders would be forced out of their roles and to the back bench in 2019.

Some Republicans untainted by scandal aren’t even finishing out their terms. Representative Pat Tiberi of Ohio left office in January to take a job with the Ohio Business Roundtable, and Dent announced in April that he would resign within a few weeks, having apparently determined that with the campaign season approaching, Congress wasn’t likely to get much more done this year. Meehan resigned on April 27 after earlier announcing plans to retire at the end of his term. Meehan wanted to short-circuit an investigation by the House Ethics Committee into allegations of inappropriate behavior towards a staff member, and he said he was repaying the government $39,000 for money used to settle the harassment case.

The trend to this point gives a distinct edge to the Democrats. While roughly the same number of lawmakers in both parties are leaving their seats to run for higher office, just 11 House Democrats are retiring outright or have already resigned, compared with 28 Republicans. (House members running for other offices often count as retirements, because it’s usually impractical or illegal to run for multiple positions at the same time.)

And although Democrats must defend far more Senate seats than Republicans in 2018—including several in states that Trump won—all of the party’s incumbents are currently running for reelection. The retirements of Corker and Flake, along with a Democratic victory in December’s special election in Alabama, give Democrats an outside chance at retaking the Senate majority. In the House, they’ll need to pick up a net 23 seats.

Data sources: Each district’s presidential-election results are from the Daily Kos. House and Senate election results are from the Associated Press.

Senate Republicans Retiring Outright

Bob Corker, Tennessee

2016 presidential election: +26.15 Trump

2012 Senate election: +34.6 Corker

The chairman of the Senate Foreign Relations Committee opted against running for a third term and promptly intensified his criticism of the president, whom he had praised during the election. Trump alleged that Corker “begged” for his endorsement, while Corker said it was Trump who urged him to run again.