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PORTLAND, Maine (AP) — Independent U.S. Sen. Angus King is seeking another term that would make him the oldest senator to serve from Maine, but three candidates are vying to end his three-decade political run.

King, who was first elected to the Senate in 2012, said he still can help bridge the gap in an increasingly divided Washington, expressing concern that “we’re losing the middle in the Senate.”

“I think I have a role to play to bridge the divide, to listen to people, to bring people together and to compromise to solve these difficult issues,” he said when he launched his reelection bid.

King is being challenged by Republican Demi Kouzounas, a former GOP state chair, dentist and U.S. Army veteran, and Democrat David Costello, a former senior government official who led the Maryland Department of the Environment and the climate and clean energy program at the Natural Resources Council of Maine. Also in the race is another independent, Jason Cherry.

Maine uses a voting system that allows residents to rank candidates on the ballot. If there’s no majority winner, the last-place candidate is eliminated, those voters’ second-choices are applied, and the votes are reallocated.

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The 80-year-old former governor would be the oldest senator in state history if he completes a third term ending in 2030, but he was not dogged during the campaign by questions about his age like President Joe Biden was before stepping down as the Democratic presidential nominee.

King has survived a pair of cancer scares. He was treated for malignant melanoma — a skin cancer — at 29 and had surgery for prostate cancer in 2015.

In Washington, he is part of an increasingly small number of senators in the middle with the departure of Democratic Sens. Joe Manchin and Kyrsten Sinema, and Republican Sen. Mitt Romney.

King has long said he doesn’t want to be tied to any party, though he caucuses with Democrats, and that served him well in a state where independents used to represent the largest voting bloc. But both major parties have overtaken unenrolled voters in sheer numbers in recent years.