AFTER ANY mass shooting, a vocal faction in Congress insists that Americans would be safer if more people carried guns into restricted public places. Allowing teachers to carry firearms on campus struck us as not helpful. But now that Fort Hood, Tex., has seen its second rampage in five years, the argument seems stronger when applied to military bases: Aren’t they filled with well-trained, trustworthy marksmen who could take down would-be mass murderers? Why not allow military personnel to carry weapons on base?

Rep. Michael McCaul (R-Tex.), chairman of the House Homeland Security Committee, thinks Congress should look into changing Defense Department policy on who can carry guns on military facilities, perhaps extending the privilege to “senior leadership at these bases, officers and enlisted men that you can trust,” he said on Fox News. Rep. Steve Stockman (R-Tex.) introduced a bill, the Safe Military Bases Act, that would lift firearm restrictions on base.

Many current and former commanders disagree, including Lt. Gen. Mark Milley, Fort Hood’s chief. These officers are right, and lawmakers should not impose their views on those who run these military bases.

The Defense Department has considered, twice, whether putting more guns in the hands of on-base personnel would make its facilities safer: after the 2009 Fort Hood shooting and after last year’s Washington Navy Yard massacre. Both times, Defense Department spokesman Damien Pickart said, the Pentagon declined to change policy, deciding that arming more people on base would pose safety problems and that the military would have to provide a lot of additional, costly weapons training.

One major concern is that disagreements inevitably arise among co-workers, whether soldier or civilian; base commanders should not want to make it easier for escalating fights to turn deadly. Another is that even well-meaning people can miss with a shot or accidentally discharge a weapon. “Even in the military, there’s varying levels of training and capability at using weapons,” Steve Bucci, a Heritage Foundation analyst and former Army commander, told the Christian Science Monitor. Both are reasons for a clear delegation of on-base safety to people who are on duty and trained to provide close-quarters security outside of a battlefield context.

The Defense Department’s policy is more flexible than those at many secure public places. Base commanders can authorize certain people to carry weapons, a prerogative we hope they use sparingly. That this flexibility exists, though, makes it all the more puzzling that lawmakers think they need to get involved. If Congress must do something, it should examine whether the Pentagon has enough military police or needs to invest more in well-organized, official on-base security.