US-POLITICS-GUNS-NRA

A convention goer holds a Thompson .45 submachine gun at the 142nd annual National Rifle Association(NRA) Convention at the George R. Brown Convention Center May 4, 2013 in Houston, Texas. The Thompson is an American submachine gun, invented by John T. Thompson in 1919, that became infamous during the Prohibition era. It was a common sight in the media of the time, being used by both law enforcement officers and criminals. The Thompson was also known informally as: the "Tommy Gun", "Trench Broom", "Trench Sweeper", "Chicago Typewriter", "Chicago Piano", "Chicago Style", "Chicago Organ Grinder", and "The Chopper". AFP PHOTO / Karen BLEIER (Photo credit should read KAREN BLEIER/AFP via Getty Images)