In a stealth maneuver, President Bush has signed into law a provision which, according to Senator Patrick Leahy (D-Vermont), will actually encourage the President to declare federal martial law (1). It does so by revising the Insurrection Act, a set of laws that limits the President's ability to deploy troops within the United States. The Insurrection Act (10 U.S.C.331 -335) has historically, along with the Posse Comitatus Act (18 U.S.C.1385), helped to enforce strict prohibitions on military involvement in domestic law enforcement. With one cloaked swipe of his pen, Bush is seeking to undo those prohibitions.
They usually call this 'Martial Law'.
There's a reason you separate military and the police. One fights the enemies of the state, the other serves and protects the people. When the military becomes both, then the enemies of the state tend to become the people.- Commander Adama, Battlestar Galactica