Correct me if I’m wrong, but I think it was more than just “allowing” it. I was under the impression that they actually ran the smuggling operation, or were complicit in it, as an intended sting operation so they could nail gun dealers along the border.
Also, so they could confirm the Democrat propaganda story that all that violence in Mexico was the doing of American gun dealers. Presumably this was approved at the highest levels. Holder at least, perhaps Obama as well.
Of the articles that I've read on it that seems an apt description: "they actually ran the smuggling operation, or were complicit in it"
As sad as it, is it would probably be better to look at the international treaty violation with Mexico (regarding the guns entering their country) rather than the murder as far as going after the BATFE goes. The reason is that the BATFE can truthfully say "we never had any say in the murder of that BP agent, in fact if he didn't have the gun we were watching he would have had some other gun" whereas they cannot weasel out of the fact that they were directly involved in smuggling weapons into Mexico in violation of the treaty with them.