HARRISBURG, Pa. (AP) — Republican David McCormick is expected to announce soon that he’ll enter Pennsylvania’s U.S. Senate race in his second bid for the office, this time to take on Democratic Sen. Bob Casey after losing in last year’s Republican primary. Senate candidates in Pennsylvania will share a ticket with candidates for president next year in a state that’s critical to whether Democrats can maintain control of the White House and the Senate. A race between Casey and McCormick could be one of the nation’s most expensive and closely watched.