FILE - This combination of images shows from left, U.S. Sen. Jon Tester, and opponent, Republican Montana Senate candidate Tim Sheehy, during a debate in Missoula, Mont., on Sept. 30, 2024. (Ben Allan Smith/The Missoulian via AP, File)

FILE - U.S. Senate candidate Tim Sheehy talks about his campaign, Friday, Feb. 9, 2024, in Helena, Mont. Sheehy is seeking the Republican nomination to challenge U.S. Sen. Jon Tester in the November election. (AP Photo/Matthew Brown, File)

U.S. Sen. Jon Tester, a Democrat from Montana seeking re-election to a fourth term, is seen at a campaign rally in a hotel ballroom, Oct. 25, 2024, in Bozeman, Mont. (AP Photo/Matthew Brown)

Republican Montana Senate candidate Tim Sheehy speaks during an election night watch party Wednesday, Nov. 6, 2024, in Bozeman, Mont. (AP Photo/Tommy Martino)

Democratic U.S. Sen. Jon Tester concedes the Montana Senate race to Republican Tim Sheehy in Great Falls, Mont. on Wednesday, Nov. 6, 2024. (Thom Bridge /Independent Record via AP)

Republican Montana Senate candidate Tim Sheehy speaks during an election night watch party Wednesday, Nov. 6, 2024, in Bozeman, Mont. (AP Photo/Tommy Martino)

People wait in line to vote outside a polling place on Election Day at MetraPark, Nov. 5, 2024, in Billings, Mont. (AP Photo/Matthew Brown)

Democratic U.S. Sen. Jon Tester concedes the Montana Senate race to Republican Tim Sheehy in Great Falls, Mont. on Wednesday, Nov. 6, 2024. (Thom Bridge/Independent Record via AP)

People fill out ballots during Election Day, at MetraPark, Tuesday, Nov. 5, 2024, in Billings, Mont. (AP Photo/Matthew Brown)

A Yellowstone County election worker places a ballot into a box at MetraPark on Election Day, Tuesday, Nov. 5, 2024, in Billings, Mont. (AP Photo/Matthew Brown)