At a Kentucky flea market, two "really nice guys" (both firearms dealers) drew guns on each other during an argument about the war in Iraq, resulting in one death. Douglas Moore, not suprisingly of the pro-war side, was released without charge after killing Harold Wayne Smith. Police said it appeared he was acting in self-defense. The case is likely the first time a dispute over the war has ended in death (domestically, that is). Ironically, Kentucky's motto is "United we stand, divided we fall."
(Via Atrios, who has more on the topic.)