Republicans are also projected to win in Montana, the third red-state seat held by Democrats. There, Republican Tim Sheehy leads Democratic Sen. Jon Tester by around 8 points, 53 percent to 45 percent (with 88 percent of the expected vote reporting). Like Brown, Tester also ran ahead of Harris, who has won only about 38 percent in Big Sky Country.

Republicans only needed to capture two seats to flip the upper chamber. They did it in West Virginia and Ohio.