From Jill Lepore, at The New York Times News Desk blog:

No one knows why Jared Lee Loughner did what he did. Maybe no one will ever know. No one can explain madmen with guns. There’s a corridor at the John F. Kennedy Library where the walls are painted black and where television monitors play, night and day, a single scene: Walter Cronkite announcing Kennedy’s death. He takes his glasses off; he looks at the clock; he puts his glasses back on. He takes them off. He says not a word. And then, he puts his glasses back on.

(via Scott Korb)