As a marker of the Republican Party’s ongoing radicalization, Doug Mastriano’s run for governor of Pennsylvania will prove revealing indeed.It isn’t just that Mastriano has openly advertised his zeal to subvert future elections. It’s also that he’s revealed this democracy-hating ethos to be underpinned by a profoundly messianic Christian nationalist streak. Will establishment Republicans rally behind such a toxic blend of extremist tendencies? Now Mastriano is bringing this question into even sharper focus. He has doubled down on the suggestion that even the most modest gun safety regulations are akin to Nazi tyranny.The Philadelphia Inquirer reports that Mastriano approvingly shared...