Click here to access article from Washington's Blog.
This blogger provides a good chronicle of the development of the US police state apparatus which has recently been strengthened by the Senate passage of an amendment to the National Defense Authorization Act which permits the indefinite, without a trial, detention of American citizens. This trend has been greatly facilitated under the cover of the War on Drugs, the War on Terror, and the 9/11 event.
I think that the impetus for this road to a police state began with the massacre of protesting Kent State students during the Vietnam War. Following this incident activists across the country were so stunned that activism diminished markedly. Other activists went underground to organize paramilitary actions.
See also this 3:47m video from Russia Today entitled, "Occupation Nation".