HARRISBURG (AP) – PA U.S. Sen. Bob Casey says he’ll seek a fourth term of office. Casey’s announcement gives Democrats a boost ahead of a difficult 2024 Senate map. Casey is a key ally of labor unions and President Joe Biden. In running for reelection, Casey has talked about landmark bills produced by a Democrat-controlled Congress that would expand spending on infrastructure such as airports and broadband, and lower drug costs for Medicare recipients. He says there’s more work to be done to help working families. Casey has cast himself as standing up to what he calls “corporate special interests.”