Gunwalking, or "letting guns walk", was a tactic used by the Arizona U.S. Attorney's Office and the Arizona Field Office of the United States Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF), which ran a series of sting operations between 2006 and 2011 in the Tucson and Phoenix area where the ATF "purposely allowed licensed firearms dealers to sell weapons to illegal straw buyers, hoping to track the guns to Mexican drug cartel leaders and arrest them" - however as of October 2011, none of the targeted high-level cartel figures had been arrested. These operations were done under the umbrella of Project Gunrunner, a project intended to stem the flow of firearms into Mexico by interdicting straw purchasers and gun traffickers within the United States. The Jacob Chambers Case began in October 2009 and eventually became known in February 2010 as Operation Fast and Furious after agents discovered Chambers and the other suspects under investigation belonged to a car club.

The Bureau of Alcohol, Tobacco, Firearms and Explosives (BATFE), commonly referred to as the ATF, is a domestic law enforcement agency within the United States Department of Justice. Its responsibilities include the investigation and prevention of federal offenses involving the unlawful use, manufacture, and possession of firearms and explosives; acts of arson and bombings; and illegal trafficking and tax evasion of alcohol and tobacco products. The ATF also regulates via licensing the sale, possession, and transportation of firearms, ammunition, and explosives in interstate commerce. Many of the ATF's activities are carried out in conjunction with task forces made up of state and local law enforcement officers, such as Project Safe Neighborhoods. The ATF operates a unique fire research laboratory in Beltsville, Maryland, where full-scale mock-ups of criminal arson can be reconstructed. The ATF had 5,285 employees and an annual budget of almost $1.5 billion in 2021. The ATF has received criticism over its handling of the Ruby Ridge siege, the Waco siege and other incidents.