ANALYSIS — Michigan Democrat Gary Peters won’t be the only senator to retire this cycle, at least according to almost a century of history. Whether it’s age or opportunity, political pressure or personal circumstances, at least two senators have left the chamber every cycle, going back to at least 1930. In fact, there’s been an average of at least five open Senate seats each election year since Herbert Hoover was president and there were only 48 states in the union. More recently, the number of open Senate seats has varied from nine in 2024 to as few as three in 2018 and four in 2020. And typically, no party is spared. Both Republicans and Democrats have had at least one open Senate seat in 43 of the past 48 election cycles. The last time a party didn’t have an open seat was 2018, when every Democratic incumbent who was up that year ran for reelection. Open seats can be more difficult to defend without the benefits of incumbency, and open-seat primaries can attract ideological candidates who become general election liabilities. This cycle, with a limited initial battleground, Senate Democrats need a lot to go right to gain the four seats they need for a majority. And having to defend an open seat in Michigan only makes things a little more difficult for them at the outset. Who's next Sen. Mitch McConnell of Kentucky is the most likely to join Peters at the exits. The 82-year-old incumbent has had multiple public health episodes. He’s already given up his position as Senate Republican leader, and his vote against the confirmation of Pete Hegseth for Defense secretary confirms that he doesn’t fear potential retribution by President Donald Trump in a primary. But even an open seat would be challenging for Democrats in a state Trump just won by more than 30 points. Beyond McConnell, the list of potential retirements looks thin. Eighty-one-year-old Republican Sen. Jim Risch of Idaho should be on the list just based on age. But Peters, 66, is evidence that it’s not just the oldest senators who leave. Republicans can’t afford to have Sen. Susan Collins retire in Maine, a state Trump lost by 7 points last fall. But Collins has indicated that she’s running — and GOP strategists confirm she’s in for a sixth term. Republican Sen. Thom Tillis of North Carolina is only in his second term, but it has felt on occasion that he was ready to walk away from the Senate. He’s already raising money for a competitive reelection race, but there’s plenty of time for him to decide he’s had enough. Sometimes, appointed senators don’t run for election — see California Democrat Laphonza Butler in 2024. But there’s no reason to believe Florida Republican Sen. Ashley Moody and Ohio Republican Sen. Jon Husted won’t run in next year’s special elections to fill the remainder of their predecessors’ terms. Moody was already term-limited in her former office as Florida attorney general, while Husted gave up his dream of becoming Ohio governor to serve as JD Vance’s successor in the Senate. Texas Sen. John Cornyn has said he's running for a fifth term. But after not getting the majority leader position, the prospect of a potentially competitive primary fueled by an emboldened GOP base might not be what the 72-year-old incumbent is looking for. There’d be a competitive Republican primary race without him, but Democrats are going to think twice about competing statewide in Texas in the near future after recent big losses. Democrats could see some of their own leave too. Rhode Island Democratic Sen. Jack Reed, 75, told WPRI in November that he was planning to run for a sixth term but that it was not set in stone. “If he retires, all hell breaks loose on the Democratic side,” said local politics guru Ted Nesi, given that there hasn’t been an open Senate seat in the Ocean State in almost 30 years. Even in an open-seat scenario, though, the general election isn’t likely to be competitive, considering Republicans don’t have any strong prospective challengers on the bench. Democratic Sen. Richard J. Durbin of Illinois, 80, has to be considered a potential retirement at his age. He told CNN’s Jake Tapper last month that he’d make a decision on seeking a sixth term by early this year. Even though Trump narrowed his losing margin in Illinois from 17 points in 2020 to 10 points last year, most of the open-seat fighting will likely be on the Democratic side. And as a former telecom executive and onetime governor, it’s possible that Virginia Democrat Mark Warner could decide he’s had enough of life in the Senate, particularly in the minority. Last cycle, there wasn’t much suspense about open seats in the race for the Senate, considering Indiana Republican Mike Braun announced early that he would forgo reelection to run for governor. Peters made sure the streak stayed alive this cycle, and there’s a good chance more senators will be joining him.
