The A.T.F. allows firearms to be bought, transported, and delivered to the Mexican Government's enemies by their enemies; the Drug Cartels and does nothing (to include their job) to stop them. Now the Mexican Government is going to sue the U.S. gun makers and distributors? Why aren't they taking the A.T.F. to court. After all, while they were watching guns travel south of the border, while telling Mexican authorities that they were stopping the before mentioned guns.
That's like suing a golf club maker for manufacturing, distributing, and selling golf clubs; because some crazy lady broke the window of your car with one. That analogy makes as much sense as the Mexican Government suing U.S. gun makers.