Yesterday's Trump appearance on Jake Tapper was his most alarming interview yet this election season, and Trump has given a ton of alarming interviews. Tapper repeatedly asked whether Trump would disavow the support of David Duke or the KKK, and Trump three times refused. Trump's pathetic excuse for refusing to do so was that he "didn't know anything about" David Duke or the KKK and promised that if Tapper would name the groups, he would "research them and get back to you."
Tapper then responded, "Well, I'm talking about David Duke and the Ku Klux Klan, so...." Trump still wouldn't bite, claiming ignorance of the most notorious white supremacist group in history and its most famous modern figurehead.
In order to believe that Trump doesn't know who David Duke or the KKK are, you would have to believe that Donald Trump is an idiot. I do believe that Donald Trump is an idiot, but even that doesn't excuse him here, because in an interview in 2000 (hat tip savingtherepublic.com) Trump knew immediately and off the top of his head who David Duke was, and furthermore labeled him as a "racist, a bigot, a problem." He went on to say, "He's obviously not the sort of person you want to have in your party." My how things have changed in the last 16 years for Trump.