Democratic Sen. Gary Peters of Michigan announced Tuesday that he will not seek reelection in 2026, leaving Congress at the end of his second term and opening up a highly competitive battleground Senate seat.

They will need to defend an open seat in a battleground state that President Trump carried in 2024. And Gov. Gretchen Whitmer ruled out a run.

The surprise decision Tuesday again complicates for Democrats in Michigan, who will be forced to defend an open seat in the battleground state for the second straight election cycle. Peters led the Democrats' Senate campaign efforts from 2021 to 2025 and helped the party hold control of the chamber in 2022 before Republicans flipped it last year.

Democratic Michigan Senator Gary Peters has announced he will not seek a third term in 2026, giving Republicans a top target in a state likely to become a major midterm battleground. Peters, who won reelection in 2020 by a narrow margin of less than 2 points, surprised many with his decision.

Democrat Gary Peters' announcement means Michigan will have an open U.S. Senate seat for the second time in two years.

Democratic Sen. Gary Peters won’t seek reelection in 2026, kicking off what could be a crowded primary to replace him in the battleground state of Michigan. Peters, 66, told The Detroit News that it is time for a “new chapter” that focuses on spending more time with his family.

Michigan Sen. Gary Peters announces he won't run for reelection in 2026, prompting speculation on his replacement, with Pete Buttigieg as a potential candidate.

LANSING, Mich. (AP) — Michigan Sen. Gary Peters, who led the Democrats' Senate campaign efforts the past two election cycles, has announced he will not seek a third term in 2026, creating a highly contested battleground seat expected to be coveted by both parties.

Democratic Michigan Sen. Gary Peters says he will not seek a third term in 2026, creating a highly contested battleground seat (AP video: Mike Householder)

Mich., says he's considering a run for U.S. Senate days after Sen. Gary Peters, D-Mich., announced he would not seek re-election.

U.S. Sen. Gary Peters announced this week he will not seek reelection, setting the stage for a potentially crowded 2026 race.