Why did American military involvement in Vietnam fail?  In this article, David McGill explains why the United States never had a realistic chance of defeating the North Vietnamese and their Viet Cong allies.

The decision by the United States government to become involved in supporting the South Vietnamese government against the communist North and their Viet Cong allies was one that would cost both America and Vietnam dearly. This article looks at why the Americans became involved in Vietnam, and also why they adopted the strategy that they did. It suggests that a degree of American involvement in Vietnam was probably inevitable, given their fundamental assumptions about how to defeat communism in Asia. The military policy they adopted to win the war was inherently flawed. It was based on the mistaken assumption that ‘coercive diplomacy’ would be effective in forcing the North Vietnamese to withdraw from the South and negotiate a settlement. This strategy was confirmed with the launch of Operation Rolling Thunder in March 1965, which marked the start of the major escalation of the conflict and demonstrated that the American leadership was pursuing a policy of trying to bomb the North Vietnamese into a negotiated peace. By 1968 it was clear that this strategy had failed and American withdrawal, albeit gradual, was inevitable...