The recent shooting spree in Tucson has brought attention to the ugly rhetoric in American politics as if it was a recent thing.
A Republican I know, a man in his 80s, has told me more than once that a woman he worked with in 1963 made no secret how pleased she was when John Kennedy was shot.
In a nation founded on a war of independence from its colonial parent and then advanced with systematic genocide against the indigenous people of North America, violence is part of our fundamental makeup. A large chunk of this nation insisted it was their right to enslave persons of African descent they had imported and bred for servitude, until the issue came to a head in the 1860s and the nation fought a long, bloody war over it. Once the official war was over, the subjugation of those African Americans continued, even as the country returned to its westward expansion at the expense of the aboriginals.
When cattlemen and sheep herders had a conflict, guns were drawn. When labor got uppity and demanded concessions from the privileged management class, goons beat them into submission. Examples abound of force crushing reason throughout our nation's history. Those are only the recent chapters in the history of our species.
Evolution moves very slowly. In every generation, more and more people do see that humans need to move on to more intellectual, less brutal forms of conflict resolution. A more cooperative society emerges, excruciatingly gradually. Attempts to force a revolutionary change of mind and heart always meet intractable opposition. Will we destroy ourselves before understanding becomes widespread? I probably will not live to find out. Visionaries envision, but grunts continue to obstruct. People who think that killing somebody actually proves something keep doing their thing, making the actual task of governing more difficult than it already is.