The training, which leaders say is not intended to be applied outside the simulated Explorer setting, can involve chasing down illegal border crossers as well as more dangerous situations that include facing down terrorists and taking out “active shooters,” like those who bring gunfire and death to college campuses. In a simulation here of a raid on a marijuana field, several Explorers were instructed on how to quiet an obstreperous lookout.

“Put him on his face and put a knee in his back,” a Border Patrol agent explained. “I guarantee that he’ll shut up.”…

Their hearts pounding, Explorers moved down alleys where there were hidden paper targets of people pointing guns, and made split-second decisions about when to shoot. In rescuing hostages from a bus taken over by terrorists, a baby-faced young girl screamed, “Separate your feet!” as she moved to handcuff her suspect.

In a competition in Arizona that he did not oversee, Deputy Lowenthal said, one role-player wore traditional Arab dress. “If we’re looking at 9/11 and what a Middle Eastern terrorist would be like,” he said, “then maybe your role-player would look like that. I don’t know, would you call that politically incorrect?”