Pennsylvania’s primary election on Tuesday will determine the nominees for key Senate and U.S. House seats, as well as other down-ballot offices. The primary will test the strength of progressive and moderate Democrats, with incumbents facing challenges from the left. Republicans are eyeing potential flips in Democratic-held seats, particularly in the Lehigh Valley and Bucks County. The outcome of these races could influence the competitiveness of the general election matchups and the future ideological positioning of the parties.