Senator Jeanne Shaheen, a Democrat from the U.S. state of New Hampshire, will not seek reelection next year, a decision that will end the longtime senator's historic political career and deals a significant blow to Democrats who were already facing a difficult path to reclaiming the Senate majority.

Shaheen was the first woman elected to serve as both governor and senator in the United States. She turned 78 in January.

A spokesperson confirmed her decision through email.

Even before Shaheen's move, Democrats were facing a challenging political map in next year's midterm elections — especially in the Senate, where Republicans now hold 53 Senate seats compared with the Democrats' 47, including two independents who caucus with Democrats.

The party that controls the Senate majority also controls President Donald Trump's most important political and judicial nominations — and his legislative agenda.

At least for now, Maine represents the Democrats' best pickup opportunity in 2026. Senator Susan Collins, the sole Republican senator remaining in New England, is the only Republican serving in a state Trump lost who's up for reelection.

But with a four-seat advantage in Congress' upper chamber already, Republicans have legitimate pickup opportunities in Georgia, Michigan and now New Hampshire.

Shaheen has been a political force in New Hampshire for decades and climbed through the ranks of Senate leadership to serve as the top Democrat on the powerful Senate Foreign Relations Committee.

She likely would have been easily reelected had she sought another term.

Former Massachusetts Senator Scott Brown, who served as ambassador to New Zealand in the first Trump administration, was considering a New Hampshire Senate bid even before Shaheen's announcement. Brown challenged Shaheen unsuccessfully in 2014.

New Hampshire has narrowly favored Democrats in recent presidential elections, but the state has a long history of electing leaders from both parties. Republican Governor Kelly Ayotte was elected last fall, when Trump lost the state by less than 3 percentage points.

Shaheen became the first woman elected New Hampshire governor, in 1996. She served for three terms and was later elected to the Senate in 2008.