Video of Obama admitting he knew about F & F (watch clip – note dates):
Here is one possible – I would say the likely reason behind F & F:
Documents obtained by CBS News show that the Bureau of Alcohol Tobacco, Firearms and Explosives (ATF) discussed using their covert operation “Fast and Furious” to argue for controversial new rules about gun sales.
Since the beginning of the Fast and Furious scandal, some avid gun-rights supporters have been suggesting that the operation was designed to promote gun control: The Obama administration sent a bunch of guns south of the border hoping to make the Mexican drug wars more violent, so that it could use the violence and the presence of American guns as an excuse to implement stricter gun-control measures. I have been (and remain) highly skeptical of this explanation — I do not think the Obama administration is quite that evil, and even if it were, the risk of getting caught would be too great to make such a project worthwhile.