The use of drugs by the American military in Vietnam was not a recognizable problem during the early stages of the war. However, as the conflict dragged on, drug use among the troops became symptomatic of the larger problems facing the United States when it came to dealing with what would become America's longest and most unpopular war.

The army that arrived in Vietnam in 1965 may have been the best trained, the best armed, and the best supplied force the world had seen up to that point. In addition, its morale and dedication to achieving its objectives were both unquestionable. However, by 1968, that fine army had disappeared, and in its place was a force less interested in search-and-destroy than in search-and-evade, which focused on avoiding conflict rather than engagement. That evasion took the form of soldiers refusing to salute superiors, refusing to fight, and...