To paraphrase Justice Cardozo ("proof of negligence in the air, so to speak, will not do"), there is no such thing as responsibility in the air. Those who try to connect Sarah Palin and other political figures with whom they disagree to the shootings in Arizona use attacks on "rhetoric" and a "climate of hate" to obscure their own dishonesty in trying to imply responsibility where none exists. But the dishonesty remains.
To be clear, if you're using this event to criticize the "rhetoric" of Mrs. Palin or others with whom you disagree, then you're either: (a) asserting a connection between the "rhetoric" and the shooting, which based on evidence to date would be what we call a vicious lie; or (b) you're not, in which case you're just seizing on a tragedy to try to score unrelated political points, which is contemptible. Which is it?
Mark David Chapman, upon murdering John Lennon, had a copy of Catcher in the Rye in his pocket. Should we have excoriated J. D. Salinger? The Unabomber had a well-annotated copy of Earth in the Balance in his dismal Montana shack. Should we have told Al Gore to watch his mouth?
One last thing -- Gabrielle Giffords offered the proper response in the well of the House.