I suspect this has many more levels than just walking guns to drug cartels.
It has been known for some time that high level government “personages”, very powerful people, are deeply involved in the drug smuggling business.
The Sinaloa cartel uses most of the smuggling routes through Arizona; that state wanted to secure their border and the Obama Administration stopped them with a court order. This directly benefits the Nation of Islam, in Chicago, which uses its so-called religous buildings for stashing drugs.
So - who in our government, who in the Mexican government, and how many fat-cat businessmen and holy-rollers are getting rich of the deaths and misery of millions?
Most importantly, are they concerned in the least that the whole situation could erupt into a hot war along the border?
I am sure that many US politicians get kickbacks from laundered money and are loathe to stop the drug trade/cartels.
Time for pitchforks, torches, tare and feathers.