On Fri, 5 Oct 2001, Tim May wrote:
It's called "Posse Commitatus," and it's clear that troops cannot be used on U.S. soil.
There have been a _few_ cases where regular armed forces were deployed in emergencies. Of course, the War of Northern Aggression was one massive terror action and the army was of course deployed.
The recent deployments in airports are of the National Guard. These units are under controls of _governors_ of states, and are not covered by Posse Comitatus. "Calling in the National Guard" has been common for many decades.
There's talk about using regular army troops at the Capitol: WASHINGTON (CNN) -- Authorities at the nation's Capitol building are considering bringing in military troops to supplement U.S. Capitol police officers and enhance security. [...] Nichols said authorities were "considering Department of Defense support." That means the troops involved could be National Guard troops or they could be regular Army troops or from another branch of the military. [...] From: http://www.cnn.com/2001/US/10/11/rec.capitol.vehicle.ban/index.html -MW-