Donald Trump, the current front-runner in the race for the Republican presidential nomination, on Friday rewteeted a post by an account with the handle “White Genocide TM,†which gives its location as “Jewmerica.†Reuters identified the image for the account as that of George Lincoln Rockwell, a prominent figure in the neo-Nazi movement in the United States. The tweet reads: “Poor Jeb. I could’ve sworn I saw him outside Trump Tower the other day!†It includes a doctored image of rival candidate Jeb Bush, the son of former president George H.W. Bush and brother of George W. Bush, holding up...