With some caveats, this sounds about right, I think. Let's be clear: Neither Sarah Palin, Rush Limbaugh, Michelle Malkin, Sean Hannity, any conservative talker you can name, the Tea Party, or whatever, can be blamed for this act of violent horror. The problem of our toxic political discourse is real and frankly, distinct from this. Both sides, and this secnario is no different, have a rather tragic tendency to try and score political points on this tragedies, and it's wrong. The Left has done it, and it's wrong. The Right has done it, and it's wrong. Besides the fact that Loughner's ideological leanings appear to be a incoherent mess of nihilistic, antigovernment rage, I don't think the lack of Sarah Palin's map, or the DNC's map, or Kos's map, or Obama's inapt Untouchables reference would have stopped this guy.
More on this later. I'll ger pushback here, but I think Chait is right on this:
Now, I do believe there is a problem with the current political moment. Both extremes of the political spectrum can embrace apocalyptic thinking and rejection of the democratic process. The left-wing version came to the fore during the 1960s, but it is tiny and almost completely disconnected from Democratic politics. The right-wing version, on the other hand, is drawing ever more tightly into an embrace with putatively respectable Republican politics. Since the closing stages of the 2008 election, conservatives have regularly described President Obama as an alien figure and his policies a fundamental threat to American liberty. It has become normal for conservatives to hint that they will take up arms if they don't get their way politically -- a violation of the cultural norm of respecting democratic outcomes that forms the basis for the stability of our political system. Sharron Angle, not just a fringe activist but the GOP's candidate in a major Senate race, rhetorically flirted with outright sedition, and Republicans paid no attention to this, because they wanted to beat Harry Reid.
Oh, and by the way, I freely admit that as the Right has taken it to the next level under OBama, the Left did many of the same things under Bush. I could get into a discussion of who is worse, but that would be fruitless at this point.