PHILADELPHIA — National political trends are shifting in Republicans’ favor as inflation assumes an even more dominant position in voters’ minds, according to two recent polls — a potentially significant development for key Pennsylvania races that could be decided by just a few percentage points. The shifts, less than three weeks before Election Day, come after a summer in which Democrats had gained ground and hoped that fury over the end of the constitutional right to abortion might help them defy political headwinds, and President Joe Biden’s poor approval ratings. If the apparent GOP moment...