A little history...http://www.washingtonpost.com/wp-srv/local/2000/vietnam092799.htm
The Pentagon march was the culmination of five days of nationwide anti-draft protests organized by the National Mobilization Committee to End the War in Vietnam -- "the Mobe." But a singular spark was provided by the Youth International Party (Yippies), a fringe group whose leaders, Abbie Hoffman and Jerry Rubin, had announced that they planned an "exorcism" of the Pentagon. They would encircle the building, chant incantations, "levitate" the structure and drive out the evil war spirits.
Snip...When the date for shutting down the government approached, the VVAW and most of the other protesters departed, leaving behind a hard core organized by the Peoples Coalition for Peace and Justice, and its more militant Mayday Tribe. The plan was to combine massive traffic disruptions with marches on the Pentagon, the Justice Department and the Capitol over three days.
Police and anti-war protesters scuffle at Dupont Circle as the "flower power" of the mid-60s turned into something more militant.
Sounds like the upcoming "protests" in NY are going to be a repeat performance.