The Myth of Posse Comitatus
Major Craig T. Trebilcock, U.S. Army Reserve
Written Prior to 9/11
http://www.homelandsecurity.org/journal/articles/Trebilcock.htm
NOW understand
The statute only addresses the US Army and, since 1956, the US Air Force. It does not refer to, and thus does not restrict or apply to, the National Guard under federal authority from acting in a law enforcement capacity within the United States. The Navy and Marine Corps are prohibited by a Department of Defense directive (self-regulation), but not by the Act itself.[1][2] Although it is a military force,[3] the U.S. Coast Guard, which now operates under the Department of Homeland Security, is also not covered by the Posse Comitatus Act.
I knew about the National Guard, but those are under the auspices of the States, no?
Interesting about the Navy and Marines, though. I would like to think, however, that they are the least likely to invade their own people, but who knows anymore.