Longtime Rep. Jim Sensenbrenner of Wisconsin will not run for reelection next year, joining a wave of House GOP retirements.

The 21-term congressman announced his retirement Wednesday night, saying he decided it was "time to step back." Only a few hours before the 76-year-old said he would not seek another term, Rep. Bill Flores, R-Texas, also said he would retire.

Their departures adds to an exodus from the GOP caucus ahead of the 2020 election. Sensenbrenner becomes the 14th House Republican to either announce their retirement or plans to run for another office. In Texas alone, five Republicans have decided not to seek another term. (Only four House Democrats have announced plans to retire or run for a different office, most recently Rep. Susan Davis, D-Ca., on Wednesday).

The GOP departures in part reflect Republicans' desire not to serve in the House minority after controlling the chamber for eight years. Some of the districts GOP members will leave have also become more competitive in recent years as suburban areas in Texas and around the country tilt more Democratic.

Here are the Republicans currently retiring from Congress, along with the recent electoral results in their districts. The bars and percentages on the right represent margins of victory in previous election years.

Democrats may have a hard time winning either Sensenbrenner's 5th District in Wisconsin or Flores' 17th District in Texas. Sensenbrenner, the second-longest serving House member, carried his seat by 24 percentage points in 2018 even in a strong midterm for Democrats.

Flores won his district, which includes the city of Waco, by 16 percentage points last year.

Still, Democrats think they have a good chance to flip several open districts, particularly in Flores' home state. Departing GOP Reps. Will Hurd, Kenny Marchant and Pete Olson all won their Texas seats by fewer than 5 percentage points last year.

Democrats currently hold a 235-197 edge in the House (along with one independent and two vacancies). Republicans aim to cut into the advantage or win back control of the chamber, though the loss of so many incumbents could make the task more difficult.

As lawmakers return from their August recess next week, more departures could soon follow.

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