Pa., on Thursday conceded the race for Pennsylvania's Senate seat to his Republican opponent, Dave McCormick. NBC News projected McCormick's win in the hotly contested battleground state race shortly after Casey's concession,

The race has been among the closest in commonwealth history, with the two men separated by approximately a quarter of a percentage point.

Pennsylvania Secretary of the Commonwealth Al Schmidt has ordered counties to halt recounting ballots in Pennsylvania’s U.S. Senate race. The order comes a day after incumbent U.S. Senator Bob Casey conceded the race to Republican Dave McCormick.