If people can't be trusted to not sell guns to the drug dealers in Mexico then the government should take all the guns away from those type of people. A case in point:
An F.B.I. agent in El Paso has been arrested and charged with dealing guns, some of which ended up being used in gunfights between the authorities and drug dealers in Mexico, law enforcement officials said. The agent, John T. Shipley, was indicted Wednesday on charges he dealt firearms without a license for more than two years, buying the weapons from dealers on the Internet and then reselling them to unidentified buyers. Mr. Shipley sold more than 50 weapons, the indictment said. Some were recovered after shootouts between the Mexican Army and drug dealers in Chihuahua on March 8 last year that left seven dead, officials said. Mr. Shipley, who was released on bond this week, has been suspended without pay since March 2009, the Federal Bureau of Investigation said.