The Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) ran a series of "gunwalking" sting operations^[2][3] between 2006^[4] and 2011.^[2][5] These operations were done under the umbrella of Project Gunrunner, a project intended to stem the flow of firearms intoMexico by interdicting straw purchasers and gun traffickers within the United States.^[6] "Gun walking" or "letting guns walk" was a tactic whereby the ATF "purposely allowed licensed firearms dealers to sell weapons to illegal straw buyers, hoping to track the guns to Mexican drug cartel leaders."^[7]

The stated goal of allowing these purchases was to continue to track the firearms as they were transferred to higher-level traffickers and key figures in Mexican cartels, with the expectation that this would lead to their arrests and the dismantling of the cartels.^[8][9] The tactic was questioned during the operations by a number of people, including ATF field agents and cooperating licensed gun dealers.^{[10][11][12][13][14]} Operation Fast and Furious, by far the largest "gunwalking" probe, monitored the sale of over 2,000 firearms, of which nearly 700 were recovered as of October 20, 2011.^[15] A number of straw purchasers have been arrested and indicted; however, as of October 2011, none of the targeted high-level cartel figures have been arrested.^[7]