For the few readers unaware, the ATF had a harebrained scheme to assist Mexican criminals in buying guns from American dealers...for some reason that still isn't clear, and without the knowledge of the Mexican government. The scandal broke when American Border Patrol agent Brian Terry was murdered with one of these guns.
(Note--removed the video because it had switched to autoplay)
Some gun rights supporters believe that the goal was to create a problem that could be 'solved' with more ATF funding and power. I'm not sure I believe that, but I'm not sure I don't, either.