That reductio ad Hitlerum rule certainly applies now to Avigdor Lieberman, who has ordered diplomats to distribute an old photograph of Haj Amin al-Husseini, the late Nazi-loving mufti of Jerusalem, sitting next to Hitler in 1941 Berlin. The idea is that world leaders will see the picture, think of Nazis, and let the Israeli foreign minister build apartments in East Jerusalem. Or something.
It's true that the Mufti was an outrageous Nazi. It's also true that he's dead. The Palestinians of the West Bank are not Nazis. Lieberman is going to have to get used to the idea.