That's pretty much dead on.
Just like in Iraq. We're in a war over there, we kill a recently injured Iraqi who was responsible for a few Marines deaths earlier in the day, and the Marine who killed the Iraqi is in the brig now. Ridiculousness.
Preciseley. The only feasible option is to authorize military personel to shoot Mexicans and Iraqis on sight with no questions asked. That'll stop 'em.