Defense Department Role in Homeland Security

What is the role of the US Department of Defense (DoD) in homeland security? Logically, one would assume that DoD would have a prominent role to play, and it does. In its June 2005 study Strategy for Homeland Defense and Civil Support, the DoD lays out its vision for fulfilling its homeland security responsibilities.

However, increasing DoD's involvement in homeland security may require additional authorizing legislation. DoD's involvement is closely regulated by the Posse Comitatus Act which outlaws willful use of any part of the Army or Air Force to execute law except when specifically authorized by Congress or the Constitution. To get a better understanding of The Posse Comitatus Act, read The Posse Comitatus Act & Related Matters: The Use of the Military to Execute Civilian Law. An abbreviated explanation can also be found in The Posse Comitatus Act and Related Matters: A Sketch.