This gives some indication
""PHILLIPS: Tell us, I want to hear it from you, the rules of engagement for these National Guard men and women."
BLUM: Well, the rules of engagement and the rules for use of force will be universal between California, Arizona, New Mexico and Texas. We are working with our states' attorney generals to make sure that there's no contradiction amongst the rules of engagement in each of those states, and we'll build upon the time-proven rules of engagement we've used for the counter-narcotics program that we've had on the southern border for about 20 years now. "
http://www.cnn.com/2006/POLITICS/05/17/cnna.blum/index.html