Alongside praying for the victims of the evil act in Arizona, it might make sense to dust off this book by James Pierson. I don't agree with every word he writes, but Pierson is great at explaining how center-left writers desperately try to identify their small-d democratic political opponents with political violence even if the attacker did not share their ideology. Liberals in this instance resort to guilt by nonassociation through stuff about climates of hate or violent rhetoric despite the lack of evidence that the attacker was influenced by any of this stuff. As Pierson points out, liberals will try to identify their democratic opponents with a violent attack even when the attacker self-identifies with the left. Several thought to keep in mind.
1. Decency, and honesty have nothing to with the Paul Krugmans and Bill Presses of the world (no shock there to some.)
2. They don't deserve politeness or any assumption of good faith. They are trying to exploit the unburied dead to attempt to silence criticism of powerful political figures and relevant policies. They owe everybody an apology and should be treated with the coldest and most persistent contempt until they alter their behavior.