The Republican Senate candidate points to clear rulings from the Pennsylvania Supreme Court that undated and incorrectly dated mail ballots should be rejected in this year’s election.

One of Pennsylvania's two U.S. Senate seats is before voters Tuesday, with Sen. Bob Casey vying for a fourth term against challenger and businessman Dave McCormick. It is expected to be a close race and could ultimately play a role in the balance of power in the Senate.

After days of the race being too close to call, the Associated Press named Republican Dave McCormick the winner in the race for one of Pennsylvania’s two seats in the U.S. Senate, defeating incumbent Democrat Bob Casey. McCormick first addressed supporters at his election night party in Pittsburgh when the race was too close to call.