Doug Mastriano has rattled a diverse swath of Pennsylvania’s Jewish community, alarming liberal Jews with his far-right associations and remarks. MERION STATION, Pa. — Four years after the massacre at a Pittsburgh synagogue, believed to be the deadliest antisemitic attack in American history, Doug Mastriano, the Republican nominee for governor of Pennsylvania, has rattled a diverse swath of the state’s Jewish community, alarming liberal Jews with his remarks and far-right associations, and giving pause to more conservative ones. Some of those voters have recoiled from Mr. Mastriano’s opposition to abortion rights under any circumstance, or from his strident election denialism....