Okay, let's recap since this has gone so far afield that even the bat crazies, like Nbadan, are lost in their narrative...
First, and most important, there is absolutely no evidence to show Loughner was motivated by inflammatory, vitriolic, partisan, political rhetoric. None. Zilch. Zero.
What we do know is that Arizona has a law, in place, by which Loughner could have been subjected to psychiatric evaluation long before he snapped. In fact, the Sheriff that continues to rail against the Right, has had several opportunities to intervene since he said, himself, he was aware of Loughner and that he had made death threats in the past.
So, I say the blame starts with Loughner, moves through the many people who contacted him over the last few years and failed to use the tools their legislature provided to deal with the mentally ill, on to the law enforcement agency that knew he was dangerous and failed to act.
Now, about that SarahPAC ad that seems to be the focus of everyone's derision and scorn.
Who in here thinks Sarah Palin personally sat down and designed that ad? And if, as you say, she is so fond of martial imagery, where are the references to "target" or "bullseye" or "lock and load" or any other violent euphemism? There not there.
In fact, in that context and on that image, surveyor marks make more sense. Districts are geography. The marks are placed on geographic locations, not people.
Chances are a marketing intern or aide came up with bright idea on their own. Even in the 2010 mid-term elections, there are similar examples of such imagery from the other side of the political spectrum.
The Democratic Leadership Committee put out this "Targeting Strategy" graphic:
The Democratic Congressional Campaign Committee issued this one (each bulls eye represents a Republican Congressman):
And, in the realm of what might have motivated someone to "target" Congresswoman Giffords, specifically? I think The DailyKos takes the blue ribbon on that one...
Two days before she was shot, Some unbalanced frequent contributor to DailyKos posted this:
And Moulitas himself, back in 2008, "targeted" and put a "bullseye" on Giffords, along with other Democrats because they didn't tow the party line the way he thought they should.
Particularly since Kos's vitriol is more contemporaneous to Loughner's first contact with Giffords (2007), when his friends became aware he didn't like her very much, wouldn't it make more sense to put the blame there and be excoriating him? Oh wait, he's a friendly.
The Democrats have failed again. Yes, again. From JFK to Loughner, Democrats first assertion, whenever something like this occurs, is that right-wing extremism and vitrolic rhetoric caused it. Not only has that never been the case, more times than not it's turned out to be either an insane person or left-wing idiot.