It is incredibly easy to blame the right wing for escalating violent rhetoric for the attack upon Representative Giffords. After all, Sarah Palin had Giffords in her "cross hairs." And plenty of folks on that side of the spectrum have been taking the words of the Revolutionaries out of context--watering the tree of liberty with the blood of tyrants and all of that. But we might want to wait a bit. The accused assassin seems more troubled than political. He did target a Democrat, but it may have been just a visible target of convenience. We simply do not know enough to judge.
I remember jumping on the bandwagon when folks thought the Oklahoma City bombing was committed by Muslims. So, I am a bit more cautious now. I still think that the Right Wing has been far more guilty of ramping up violent rhetoric of late (at least since the Clinton Administration), and there are good reasons to believe that such rhetoric can have an impact (see this blog post for a start), especially on less stable folks. We can be critical of the Right Wing types for using extremely violent rhetoric, including Palin's "targeting" and "reloading" stuff without reference to this event.
Will this event change the political climate? It might move the middle of the electorate to be less tolerant of some of the nasty stuff, but the institutions (Fox) and the people (the Koch folks, Rush Limbaugh, etc) will still be pushing things in the same direction. I doubt that you are going to see much responsibility taken, any remorse, or reduction in the rhetoric. Folks interested in using violent terminology can blame this event on the one guy. Palin can delete the stuff from her twitter account, facebook, and the rest, and soften her language by 5%.
But perhaps the movement of the middle will make a difference in the long run. I am willing to wait and see on this one.