I don't know what the motive for the shooting in Arizona was. Anyone that tells you that they do is either a liar or the shooter. And I wont accept the easy scapegoats like Sarah Palin or Glenn Beck either.
But not knowing the specifics of that particular event won't change the grim reality that we have a problem with violence in this country. A problem with casual violence. Violence seen as a reasonable response to any of life's unpredictable twists and turns. Casual violence permeates our language to the extent that I recently heard a man declare that he would 'kill for a cigarette.' Not to take nicotine addiction lightly (I was a nicotine addict for 20+ years), but the fact that the individual in question wasn't actually killing at the time that he made that declaration was little comfort.
The common vernacular of sports holds that great players are 'warriors' even at a time when many of our young people have experienced the un-glamorous and terrifying truth that 'warrior' is something that no sane person would aspire to. War, among all human endeavors, should be condemned out of hand. War should be the bane of all sane and thinking people. The idea that the vocabulary of war is casually invoked in metaphor to describe something like a football game should be repugnant to anyone.
Likewise political speech should not require martial metaphors to be effective. War is about killing people to achieve political ends. War fighting, therefor, should be the last resort of civilized people to resolve any difference. Casually evoking the language of warfare in political discourse must be rejected. Those who use it must be held to account by all reasonable people.