Sen. Debbie Stabenow (D-Mich.) will not seek reelection in 2024, opening up a Senate seat in a key swing state that has leaned Democratic in the past few cycles.

Stabenow has been in the Senate since 2000 and in public office since 1975, when she first won election as a county commissioner in Ingham, Michigan, which includes most of the Lansing area.

She has been a popular senator, winning reelection with relative ease, and is known for her persistent advocacy on behalf of mental health and the preservation of the Great Lakes.

Stabenow’s announcement, made in an interview with Melissa Nann Burke of the Detroit News, comes months after Michigan Democrats won big in the 2022 midterms, sweeping every statewide race and gaining full control of the state legislature for the first time since the 1980s.

That victory was a factor in her decision, Stabenow told Burke.

“I think it’s important to know the time and place where you open doors again for others and pass the torch,” Stabenow said. “I feel like this is really the right time for me, it’s the right time for Michigan.”

The 2024 Senate map already looks difficult for Democrats because of the number of vulnerable seats they have to defend. But the party has no shortage of plausible candidates with records of political success in Michigan.

That list features several members of the state’s U.S. House delegation, including Reps. Debbie Dingell, Elissa Slotkin, Haley Stevens, as well as local and statewide officials, such as Secretary of State Jocelyn Benson, Detroit Mayor Mike Duggan and Lt. Gov. Garlin Gilchrist.

Gov. Gretchen Whitmer, who won reelection decisively, would also be a formidable candidate. But she has said she intends to serve out her second term ― and is widely thought to have her eyes on higher office the next time Democrats need a presidential nominee.

Stabenow’s nearly 50-year career spans an era in which women took on a much greater role in politics, and Stabenow did her part to help push that transition along. She has said she was the first sitting member of the Michigan state House to have a baby while in office and the first woman to preside over the state House as assistant speaker.

“I remember the talk among the speaker and others at the time that ― would I be able to get the attention of the House? Would I be able to call them to order and get their attention and be able to manage?” she told Burke. “And so when I first got up there, I took the gavel and just whacked it so hard that a chip of it went flying across the room.”

Stabenow was also the first woman to serve as a U.S. senator from Michigan.

In 2009, she made headlines ― and created a viral moment ― during the debate over the Affordable Care Act when a Republican colleague questioned a proposed requirement that insurance cover maternity care.

The Republican senator said that, as a man, he didn’t need maternity coverage. Stabenow responded quickly, “I think your mom probably did.”