The scandal that started it, how executive privilege works, and what might come next in the House investigation
What is Fast and Furious?
For years, the U.S. government ran an elaborate "gunwalking" operation on the Mexican border. It was a high-stakes sting operation in which the Bureau of Alcohol, Tobacco, Firearms and Explosives -- a part of the Justice Department -- opted not to stop purchases of weapons that it suspected were intended for smuggling across the border by traffickers. The goal was to let "straw buyers" purchase the guns and move them to large-scale traffickers, but to stop the weapons before they moved across the border. It's a method that law enforcement agencies have used for some time -- the ATF was doing it at least as far back as 2006. The specific operation called "Fast and Furious" dates to 2009 and was apparently initiated by an ATF agent in Phoenix.
Did it work?
Not really -- Justice can't point to a single instance of a major boss the operation took down. But as one might imagine, the ATF was unable to keep track of all of the guns. In fact, the agency managed to lose track of some 2,000 guns. Those weapons were later connected to various violent crimes. Most notably, two were found at the scene after a Border Patrol agent named Brian Terry was killed in a firefight on December 10, 2010 with suspected illegal immigrants in Arizona (it's unclear whether one of the guns fired the bullet that killed him). Reports following that murder revealed that the guns had been part of a tracking operation.