Republican David McCormick is narrowly trailing Sen. Bob Casey (D-PA) in Pennsylvania’s highly contested U.S. Senate race, according to a new poll.

In a hypothetical general election showdown, Casey is leading, 45% to McCormick’s 41%, with 14% undecided, per an Emerson College Polling/the Hill survey of 1,000 registered Pennsylvania voters from Sunday to Wednesday. Compared to a February poll in which he was 10 points behind, McCormick has begun to close the gap on the Democratic incumbent’s lead.