The law, was championed by far-sighted Southern lawmakers in 1878. They had experienced a fifteen year military occupation by the US Army in post-Civil War law enforcement. They understood the heel of a jackboot.
In a nutshell, this act bans the Army, Navy, Air Force and Marines from participating in arrests, searches, seizure of evidence and other police-type activity on U.S. soil. The Coast Guard and National Guard troops under the control of state governors are excluded from the act.
Deputy Defense Secretary Paul Wolfowitz, testifying in October before the Senate Armed Services Committee, agreed that it might be desirable to give federal troops more of a role in domestic policing to prevent terrorism. "In certain cases we can do more than anyone else in the country because of the special capabilities that we have,'' he said.
Dennis Corrigan, a retired colonel who taught the law at the Army's Judge Advocate General's school, says legislators should resist the urge to change it. The military isn't trained to be a police force, he says, so it should stick to the skills for which it is trained: surveillance, information gathering, logistical support. All of these activities are allowable under Posse Comitatus...
http://www.dojgov.net/posse_comitatus_act.htm
I had to miss some of the Homeland Security briefing.
Has the LA Governor done anything to permit the military to operate in a law enforcement capacity in New Orleans?