How the Pennsylvania Senate race got so close

This past summer, polling had Lt. Gov.John Fetterman up by as much as 12 points in the Pennsylvania Senate race, a sizable lead in a swing state that’s typically pretty close.

Fetterman’s support raised Democrats’ hopes of flipping the seat, particularly since President Joe Biden won there in the last cycle. Since then, however, the race has tightened considerably, a byproduct of Republican voters “coming home” to candidate Mehmet Oz, and GOP investments in attack ads going after Fetterman’s record on crime. Fetterman now leads Oz by six points, according to the FiveThirtyEight...