From Wikipedia for that its worth
In early 2005, the pistol was subject to intense controversy in the United States after the Brady Campaign stated that commercially available SS192 ammunition penetrated a Level IIA Kevlar vest in testing. The National Rifle Association (NRA) shortly countered the Brady Campaign's claim by pointing out that the gun control group may not have adhered to standard testing procedures, and that FN only offers armor-piercing varieties of the 5.7×28mm cartridge to military and law enforcement customers. Varieties offered to civilians are classified by the U.S. Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) as not armor-piercing, and it was stated that the SS192 and SS196 cartridge variations were unable to penetrate various types of Kevlar vests in tests conducted by FNH USA.
Also looks like the antis have been trying to push this bill every other year since 2004.