The film tells the story of how, from the very start of the war, such as with the Green Berets, there was resentment within the ranks over the difference between the conflict in Vietnam and (as Jane Fonda and others state in the film) the "good wars" that their fathers had fought. In the beginning some servicemen simply left the military as individuals; according to Pentagon figures, between 1966 and 1971 there were over 500,000 incidents of desertion in the U.S. military. Over time, however, it became apparent that so many were opposed to the war that they could speak of a movement. Howard Levy noticed this when he stopped training soldiers and got a lot of support from fellow soldiers. Protest newspapers started to be printed. This resulted in a severe crackdown by the Army, sending people to prison for years. The organiser of one protest newspaper was sent to prison for ten years for the alleged possession of marijuana.
Another cause for discontent was that a large number of the soldiers sent to the front were black and at the time a black movement was rising. One notion was that blacks should only fight against black oppression and that was not going on in Vietnam, so blacks should not go there. This resulted in one revolt, at the Long Binh Jail in South Vietnam in August 1968, in which one white soldier was killed.
The movement eventually made the U.S. Army almost unoperable. In response to this, U.S. president Richard Nixon decided to "Vietnamise" the war, leaving the ground fighting to South Vietnamese troops and limiting U.S. involvement to bombardments. As a result, the presence of U.S. soldiers at the border was denied, leaving these soldiers to fend for themselves. When six of these soldiers were ordered to go on what was effectively a suicide mission, they refused and instead decided to send a message to the home front. Nixon responded to this by pulling that company out, but then other companies started to stop fighting as well. Some officers were killed by their own men. Because this was often done with fragmentation grenades, it became known as fragging.
When, during one offensive, more bombs were dropped on Vietnam than were used during the whole of World War II (by both sides), the Navy also started to protest. A ballot was cast on the aircraft carrier Constellation, in which the crew decided not to go to Vietnam.