The
New York Times has an article today relevant to Emma's point.
"U.S. Is Arms Bazaar for Mexican Cartels"
A quote:
Mexican authorities have long complained that American gun dealers are arming the cartels. This case is the most prominent prosecution of an American gun dealer since the United States promised Mexico two years ago it would clamp down on the smuggling of weapons across the border. It also offers a rare glimpse of how weapons delivered to American gun dealers are being moved into Mexico and wielded in horrific crimes.
italics mine