Sometimes in politics, you simply have bad luck:
One angle regarding the Giffords/Palin debate that's not been mentioned is the fact that sometimes in politics, you experience nothing more complicated than "bad luck". In the case of Palin, she put out a graphic with a crosshairs "on" Giffords, and months later, someone shot the congresswoman. So you have a connection - fair or not - that gets people talking.
Ann Coulter suggested McVeigh should have bombed NY Times building. Nobody did do that. But if it had happened (in a fashion clearly unrelated to what she said), Coulter would be in hot water.
Palin, by using crosshairs, took the gamble that it was worth the political upside to use gun metaphors but with the attendant risk that a shooting might take place. It did. Palin lost that bet. Most people would accept that unfortunate outcome as bad luck, not fight the issue, and move on. Palin won't.
Palin had a chance to back off when Giffords called her on the gunsight map back in March 2010. She didn't but doubled down. Now she has to pay the price.
It's a Greg Stillson (Dead Zone) moment, a Lonesome Rhoades (Face in the Crowd) moment for her. She's not handling it well but then neither are the rest of the Repugs. Boehner chooses a party fundraiser over going to Tucson. No national solidarity with that black impostor for him.