The shooter, Jared Lee Loughner, seems to have been mentally ill, and neither right-wing nor left-wing, but just nuts. (He is a white male, and identified as such in this story.)
However, the usual inquisitors (not the usual suspects—you and I are the usual suspects) are blaming Sarah Palin and "rhetoric."
"Let me be clear, as a great man says: If you’re using this event to criticize the ”rhetoric” of Sarah Palin or others with whom you disagree, then you’re either asserting a connection between the ”rhetoric” and the shooting – which based on evidence to date would be what we call a vicious lie – or you’re not, in which case you’re just seizing on a tragedy to try to score unrelated political points, which is contemptible. So which is it?"The most annoying blame game example is from Sheriff Clarence Dupnik, who is quoted as saying ”Arizona has become the Mecca for prejudice and bigotry."
Dupnik is notorious for having said he'd refuse to enforce SB 1070. His anti-SB 1070 position is so radical that he was actually published on Opinion page of the Wall Street Journal:Arizona's Immigration Mistake May 5, 2010