Donald Trump has centered his unlikely rise from reality television star to onetime — and potentially future — president on the idea that he's wiser than Washington's bumbling political class, once going so far as to label himself a "very stable genius." But when it comes to one of history's darkest moments, Trump is professing ignorance. Facing criticism for repeatedly harnessing rhetoric once used by Adolf Hitler to argue that immigrants entering the U.S. illegally are "poisoning the blood of our country," Trump insisted he had no idea that one of the world's most reviled and infamous figures once used...