HARRISBURG (AP) – An announcement is expected today by Republican David McCormick that he’ll enter PA’s U.S. Senate race in his second bid for the office to take on Democrat U.S. Sen. Bob Casey. A “special announcement” is to be made by McCormick in Pittsburgh at 5 p.m. PA Senate candidates will share a ticket with presidential candidates next year in a state that’s critical to whether Democrats can maintain control of the White House and the U.S. Senate. The 58-year-old McCormick was sought to run again by the party establishment and, thus far, has a clear GOP primary field. A race between Casey and McCormick could be one of the nation’s most expensive and closely watched.