excuse for Gunwalker doesn't work?
You deliberately let illegal gun sales go through.
You deliberately let(maybe assist) the bad guys in smuggling them to Mexico.
When they TURN UP AT CRIME SCENES you say you're using that data to build a case.
Really? ON WHO, you lying bastard? A cartel chief who's in MEXICO and they already know he's smuggling drugs and ordering murders? Do you actually think saying 'I'm from BATFE and I have a warrant for your arrest!' is going to be the magic phrase that puts him in jail? For real?