This seems like a part of the silent social contract: A person can express a preference for a political ticket on that person's personal automobile with a reasonable expectation that no one is going to try to run said automobile off the road.
Unfortunately, some people seem to have rejected that notion.
In Nashville yesterday, a man picked up his 10-year-old daughter in his car that sports the natty Obama-Biden sticker from the federal election in 2008. Another motorist notices the sticker and proceeds to follow, honk at and give the finger to the man. This continues until the other motorist decides to run his SUV into the back of the man's vehicle and then, instead of driving away or getting out and exchanging insurance information, the motorist guns his engine and pushes the combined mass of motor vehicle nearly onto the sidewalk.
The aggressive motorist faces a charge of felony reckless endangerment.
More telling yet is the story of harassment and intimidation collectively told in the comments to that news post by people who sport Obiden stickers. Honking, finger-waving, and aggressive driving is something I have never experienced myself, with my Kerry-Edwards and Defeat Bush! stickers.
Via Shakesville, with much thanks.