A reader writes:

What's most striking to me about the Obama-as-Joker posters is the white face. WHITE FACE! I'm not sure if the irony is intentional (I very much doubt it), but still. It's priceless.

It's graphically striking, but politically obtuse. The Joker is a wild man; Obama is no-drama; the Joker is an anarchist; Obama is a community organizer. Obama's careful politicking, his almost painful resistance to emotionalism, are worth lampooning, because they at least show an understanding of him, which is essential to successful mockery. But portraying him as an anarchist white terrorist recently made famous by Heath Ledger? To prove what exactly? Or is even asking for a reason at this point a silly thing to do?