The Republicans have taken back control of the Senate, ending their four-year stretch as the minority party, according to projections.
By midnight on Tuesday, Bernie Moreno had ousted Sherrod Brown in Ohio, while Jim Justice won the West Virginia seat held by retiring independent Joe Manchin, AP projected.
At the same time, Republicans Ted Cruz and Deb Fischer saw off close challenges in Texas and Nebraska.
The question now is how large the GOP majority will be, with races continuing into the night.
Democrats had faced an uphill battle to keep their one-person majority in the Senate, having to defend 23 seats. Republicans only had to fight to retain 11 seats.