"Evil" works for us when nothing else will. Like a pair of asbestos mitts, it enables us to handle things we could otherwise not bear to touch. "Evil" enables us to categorize and keep safe distance from people who would otherwise almost crush us with their horror, their unfathomability: Hitler, Stalin, Pol Pot, Idi Amin. And it gives us unlimited power to denounce them, to condemn them, to convince ourselves that never, never, never would we have anything to do with them. Those who are "evil" are consigned to the world of devils and demons, the underworld of those whose motivations, personalities, influences, or thoughts no longer matter. How could they? -- they're evil.
But "evil" also blinds us. It convinces us that, while some judgments are just a matter of perspective or cultural context, others are absolute, and apply universally. And yet when, in re-creations such as that in the film Argo, we see the United States denounced in billboards as "The Great Satan," we smirk and think how ridiculous that is: "What, us, Satan?"
And this is the essential problem. In the relentless march of cultural and historical amnesia that our modern media-saturated world embodies, "evil" is the ultimate memory zapper. It convinces us that all we need to know about someone is that they were "evil" -- no more sense learning about their lives or motivations. Case closed. The fact that so many of the people we write off in this manner were, in their country and in their heyday, beloved by millions and widely admired, strikes us a irrelevant. The fact that so many people who ended up being "evil" started out being "good" seems merely an inconvenient detail. When we see women holding up their babies for Hitler to kiss them, or families weeping at the funeral of Kim Jong-il, we think to ourselves, what foolish people! How were they so hoodwinked?
But perhaps it is we who wear the blinders. "Evil" works so well in retrospect; it solves for us the problem of history. But if we really want to prevent future Hitlers and Stalins from arising, it's absolutely useless. No one steps forward and calls themselves evil -- to do that would be almost comic, like Austin Powers or Aleister Crowley. No, the people who we may, eventually, find to be evil will always be people who arrived to meet some human wish or another: the wish for stability, the wish for prosperity, the wish for revenge, the wish for power. They will begin by being very attractive people indeed, so attractive that we don't see them in time to stop them -- or ourselves.