Defying American airpower, North Vietnamese troops and materiel stream down the Ho Chi Minh Trail into the south, while Saigon struggles to “pacify the countryside.” As an antiwar movement builds back home, hundreds of thousands of soldiers and Marines discover that the war they are being asked to fight in Vietnam is nothing like their fathers’ war.
http://www.pbs.org/video/resolve-january-1966-june-1967-9ejs1c/