Republicans have taken the Senate majority for first time in four years. The unexpected battleground of Nebraska pushed Republicans over the top late Tuesday. Sen.

The G.O.P. governor easily won the seat being vacated by Senator Joe Manchin III, an independent who caucused with Democrats, giving Republicans an expected win as they push to take the Senate.

The seat was left largely uncontested by Democrats after Sen. Joe Manchin announced last year he would not seek reelection.