Adolf Hitler is like that bad tooth you can't keep your tongue off, though it hurts to touch it. Seventy-two years postwar, he keeps surfacing. He fascinates. All the way up and all the way down the age scale — from Deputy Prime Minister Taro Aso, 76, who last week praised Hitler's "motives," to the teen and barely post-teen girl band Keyakizaka46, who last Halloween performed in Nazi drag — he fascinates.

There is no one in world history quite like him. Artist-manque, philosopher-manque, actor-manque, revolutionary-manque — everything about him was manque, until he turned the tables on his mockers.

"He was a sort of clown," Hitler scholar Hugh Trevor-Roper told journalist Ron Rosenbaum, author of "Explaining Hitler" (1998). "He looked ridiculous. He had this Charlie Chaplin mustache and he made these ranting speeches and people didn't take him seriously."