One of the most infuriating signs of our troubled era is that you don’t have to dig very far into the political barrel to find the antisemites. Although they have made deeper and broader inroads among Democrats, especially on the far-left, disheartening numbers of Republicans, independents and erstwhile conservatives are also guilty of embracing the ancient hatred. A common sign among the haters these days is the crackpot claim that Jews, — Israeli and American, — hoodwinked President Trump into joining Israel’s war against Iran. According to this theory, Trump and his White House were like so many innocent lambs...