In a moment that blurred the boundaries of political allegiance, Democratic Senator John Fetterman appeared by video at a Republican convention in Dallas, endorsing his GOP colleague Dave McCormick and pledging solidarity with Donald Trump on steel industry issues. The gesture, delivered from a Pittsburgh steel mill in his signature black hoodie, crystallized a years-long rightward drift that has made Fetterman more beloved among Pennsylvania Republicans than among the Democrats who elected him. It raises an old and enduring question in democratic life: when a representative's convictions migr