Well, if the investigation into gun running underpinning the Fast & Furious scheme was actually completed before someone blew the whistle on the conspiracy, it would have shown that the Justice Department had evidence it could produce, that numerous gun shops and gun shows had allowed purchases of multiple "assault rifles" to funnel weapons to Mexican drug cartels, because they had tracked the guns to murder scenes, including one inside Mexico where a federal law enforcement officer had been killed. Therefore, to stem the tide of assault weapons into Mexico, it would be necessary to ban such sales, or ban all such weapons.
I mean, who in their right mind would ever accept as a fact that the U.S. Department of Justice and ATF would be involved in gun running to Mexican drug cartels? It makes no sense. Except, we now know it did happen. And our Attorney General was held in contempt of Congress for failing to produce documents which were subpoenaed, and then the Justice Department, who would enforce such a contempt order, failed to prosecute the head of its own Department, that Attorney General.
It is a secret scheme that almost cannot be conceived as possible, but it happened. And they got away with it.