Desperadoes like Frank and Jesse James earned Missouri the nickname of the "Outlaw State" after the Civil War, and that reputation followed the region into the Prohibition era through the feverish criminal activity of Bonnie and Clyde, the Barkers and Charles "Pretty Boy" Floyd. Duck into the Slicker War of the 1840s, a vigilante movement that devolved into a lingering feud in which the two sides sometimes meted out whippings, called slickings, on...