WASHINGTON (AP) — Republican David McCormick won a Senate seat in Pennsylvania on Thursday, defeating Democratic Sen. Bob Casey and padding the GOP’s Senate majority. McCormick, 59, is a two-time Senate challenger and a former hedge fund CEO who served in former President George W. Bush’s administration. McCormick had strong support from Wall Street donors and contacts across the worlds of government, politics and finance. Casey had been seeking his fourth term and is perhaps Pennsylvania’s best-known politician, the son of a former two-term governor and Pennsylvania’s longest-ever serving Democrat in the Senate.