The brand name of Hitler is far more than his human persona and is certainly greater than his culminating acts. It is the story of a megalomaniacal man whose rise to power emerged from democratic conventions. He is a warning to all thriving and civilized democracies that the process itself can be steadily and lawfully perverted into something unrecognizable. He is a cautionary tale of how easily a population can be manipulated through propaganda and fear into committing, through acquiescence or activity, acts of unimaginable atrocity within a very short time span. We remember Hitler because we never want to forget how even representative governments can slide into dictatorships virtually overnight.
And that is why comparing Bush to Hitler isn't so much an exaggeration, it's just good common sense. No, Bush has yet to mount an organized campaign of genocide per se. But we make these comparisons now, early, when we see our leaders following an all-too-familiar path. We do this so that we don't wake up one morning to a mushroom cloud over Tehran and rue our ineptness to stop Bush from finally outpacing Hitler's body count and delusions of global domination.
Because then those of us left won't be comparing Bush to Hitler, we will be comparing Hitler to Bush.