The crux of it is that the ATF did not sell weapons - they monitored weapons sales, and then ran up against a brick wall of lax gun laws when they tried to get indictments. There was also infighting and backstabbing going on among the agents.

The big raison d'être for the start of the congressional investigation was the killing of a U.S. agent by guns supposedly sold by ATF agents to Mexican drug gangs. Except - that didn't actually happen:

I would like to see the Justice Department be able to do its job and find out how this information became public. I do have a sneaking suspicion that the GOP itself may not be as pleased with the results as they are with the ongoing witch hunt. Why? There are a number of people who think that it is quite possible that Darrell Issa may be behind these leaks. He's leaked information before, most recently, last month.

WASHINGTON -- House Oversight Committee Chairman Darrell Issa (R-Calif.) has taken the unprecedented step of leaking a secret U.S. trade document, in hopes of pressuring President Barack Obama's administration into disclosing the details of a major trade deal with far-reaching implications on everything from "Buy American" contracting rules to prescription drug prices to internet freedom.

Issa entered the sensitive, and previously undisclosed, information into the Congressional Record on Thursday during the floor debate leading up to the passage of his resolution placing Attorney General Eric Holder in contempt of Congress.

The powerful Republican might be protected from what otherwise would be a criminal offense under Congress’s speech and debate clause because the remarks were written into the public record during chamber proceedings. (snip)

The applications, which are under a federal court’s seal, were given to Issa by a mole with access to the documents. Issa has claimed they reveal that top-level Justice Department officials signed off on the documents and knew about the controversial “gun-walking” tactics used in Fast and Furious. Issa has called his source a “whistleblower” and refused to disclose his or her identity. (snip)

In testimony before the House Rules Committee this week, Issa told lawmakers that he had no evidence that Holder was responsible for Fast and Furious. But on Thursday, the California Republican successfully passed civil and criminal resolutions placing Holder in contempt for not responding to a congressional subpoena for documents.