Republican David McCormick is projected to defeat Democratic Sen. Bob Casey in Pennsylvania's U.S. Senate race.

Aside from once-and-future President Donald Trump's unexpectedly decisive win, one of the most surprising results in Tuesday's election was Republican Dave McCormick's apparent victory over three-term U.

Republican Dave McCormick won the U.S. Senate election in Pennsylvania, Decision Desk HQ projected on Thursday, beating Democratic incumbent Bob Casey in an important win for Republicans hoping to capture a majority in the chamber.