Military Expands Homeland Efforts: "The document argues that a more 'active, layered' defense is needed and says that U.S. forces must be ready to deal not just with a single terrorist strike but also with 'multiple, simultaneous' attacks involving mass casualties.
The document does not ask for new legal authority to use military forces on U.S. soil, but it raises the likelihood that U.S. combat troops will take action in the event that civilian and National Guard forces are overwhelmed. "