It is generally acknowledged that the antiwar movement in the late 1960s and early 1970s shortened the Vietnam War; how that is interpreted may depend on whether the person doing the interpretation supports or does not support the war itself. Thus, some see the antiwar effort as having prevented America from winning, while others see the antiwar effort as preventing America from continuing a wasteful and unwinnable war. The primary role of the antiwar movement was not one that caused change in and of itself but that kept the issue before the public. The public might have accepted the official version of events far longer if that version were not being questioned constantly by antiwar activists. When certain events occurred that suggested that the antiwar protesters were at least partially right, the public paid attention. Although there was ever growing dissent from citizens in America, did their actions actually help end the war in Vietnam?
The Vietnam situation was one that developed and escalated so slowly in the mind of the American people that it was not until the war had grown to massive scale that the majority of American people could actually sit down and ask to themselves what they were pulled into. American involvement in the war had been going on since 1954 when the French were forced to pull out after the battle of Dien Bien Phu.  There had always been people against the war, but it was not until more than a decade later that full scale protest groups emerged.
Although Kennedy believed that military involvement in South Vietnam would never achieve their intended goal, the Kennedy administration essentially followed the course that would be continued by subsequent administrations- to maintain a military presence because to do otherwise would make America appear weak, and to fight against communist aggression based on the domino theory that if one country fell, more would follow. 
Democratic as well as Republican presidents continued the war because of the belief that it showed American weakness to withdraw. In addition, there is clearly some feeling that once committed, America could not withdraw without achieving victory. President Lyndon Johnson let this fear of negative public opinion influence his policy in the war: "Haunted by fears of personal inadequacy, profoundly shaped by cultural norms of courage, honor, and manliness, and determined never to allow the right wing to use his policies in Vietnam as an excuse for a new McCarthy era, Johnson approached the horrible dilemma of Vietnam already wrapped in a straitjacket" 
The war went largely unexamined by the public until the Johnson administration. The war seemed to have no end in sight and the American public was finally starting to realize this. The Gulf of Tonkin Resolution publicized doubts about the war and raised questions about the policy. Opposition to the war increased as the war escalated thereafter, and certainly the more troops that were sent into Vietnam in the late 1960s, the more opposition solidified. Images of the war on television created uncertainty in the U.S. and contributed to the development of the counter-culture. Some have claimed since that time that the dissension at home is what lost the war, but it is not at all certain that the opposition at home had that much to do with the loss. It may have deepened the resolve of the communists, but nothing the U.S. had done prior to the beginning of opposition at home had been effective, raising the question of why it would have been any more effective in the late 1960s.
Several events changed the way the public saw the war, and one was the My Lai Massacre. The My Lai Massacre occurred on March 16, 1968, and saw almost 500 unarmed civilians, the majority of which were women and children, murdered by the U.S. Army.  To make things worse, some bodies were found to be sexually abused and mutilated. It wasn't until a year later that the American public found out about the murders which sparked a storm of controversy throughout the United States. Another event which turned public opinion against the war was the self immolation of a Buddhist monk in October 1963 in an act of protest under South Vietnam's President Ngo Dinh Diem's corrupt regime. 
While the antiwar movement had no single iconic leader to act as a face of the movement, many people from all walks of life participated. Martin Luther King declared his opposition to the war in 1967 in a speech where he outlined seven major reasons he was against the war. He felt that the war was diverting resources away from issues that actually needed attention and "was doing far more than devastating the hopes of the poor at home. It was sending their sons and their brothers and their husbands to fight and die in extraordinarily high proportions relative to the rest of the population."  Another famous figure who opposed the war was Muhammed Ali, who was stripped of his heavyweight title for refusing to serve in the military. Even those people unlikely to be a part of a protest movement were involved such as doctors, lawyers, housewives, and religious leaders. Anyone who knew someone who was likely to be drafted in the war was a candidate for the antiwar movement.
The most active participants in the antiwar movement may very well have been students. Students from around the nation participated in protests during the Vietnam War. Many colleges had formed chapters of Students for a Democratic society, an activist organization which strongly opposed the war. SDS expressed "that the war is immoral at its root, that it is fought alongside a regime with no claim to represent its people, and that it is foreclosing the hope of making America a decent and truly democratic society." 
A monumental event that elevated concern about the war occurred on May 4, 1970 at Kent State University in Ohio. National Guard troops were called in to quell a protest led by Kent State students to oppose the ever escalating war by President Nixon. The event ended in disaster as four students were killed and nine were injured, one of which suffered permanent paralysis from the attack.  Those injured in the attack were not only protesters but also innocent bystanders who were simply in the wrong place at the wrong time. For some, the event was proof not only that the American social and political systems were failing but that they knew it and were willing to kill young people to protect the status quo. The incident was a direct response to President Richard Nixon's speech made on television on April 30, 1970 which announced what he called an "incursion" into Cambodia by U.S. troops fighting in Vietnam. This was perceived as a widening of the war and generated protests on campuses at colleges and universities across the country. Students at Kent State University in Ohio took part in a series of actions over the weekend following that Thursday night speech, and among the actions taken were the breaking of windows in the business district and the burning of the Army ROTC building on the campus. The governor ordered the Ohio National Guard to the campus as a police action on Monday, and it was this which would lead to the shooting by National Guardsmen of several students. 
Student uprisings in the two years before 1970 saw an increase in confrontations. In 1969 there were two large-scale, national demonstrations against the war, and there were also moratoriums on many campuses throughout the country. In Kent, 4,000 people marched through the downtown area. In Washington, D.C., a demonstration attracted some 500,000 people.  The Kent State killings could be seen as the culmination of a decade of campus protest, and the response of the government demonstrated how little it understood the depth of sentiment against the war and other issues that existed at that time. It also showed how paranoid the leadership could be when confronted with any opposition.
With events like the My Lai and Kent State massacres burned into people's minds, the idea of a war with no purpose to the common person made less and less sense as time went on. Although antiwar activists cannot receive all the credit for the ending of the war in April of 1975 as the North Vietnamese sacrificed everything for their cause, the antiwar movement kept the issue alive and raised public consciousness in the Western world. While governments may routinely act against the wishes of its people, there will always come a point in time when enough people dare to oppose the government to bring about real change. This happened in the 1960s and the 1970s due to the efforts of Americans who had enough sense to admit America was wrong in its actions in Vietnam and enough courage to stand up and oppose it.
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