We should know our history.................

     Ten years after the United States had withdrawn its last man, ignominiously, from Saigon, the journalist Joseph Lelyveld observed acutely, "When we talk about Vietnam, we are seldom talking bout the country of that name or the situation of the people who live there.  Usually we are talking about ourselves.  Probably we always were, which is one conspicuous reason our leaders found it so hard to shape a strategy that fit us and our chosen terrain."  There are many ways of explaining why the United States came to grief so spectacularly in Vietnam.  But the plain fact of it will always be astounding.   The United States was not only five times more populous than Vietnam, its economy was seventy-six times larger.  In 1964 there were only around ten countries in the world, aside from sub-Saharan Africa, that were poorer than Vietnam in terms of per capita gross domestic product, at a time when the United States cam in second only to Switzerland.  Technologically the gap between the two countries—not least in the realm of armaments—was so large as to be nigh immeasurable.  Yet America lost.  Small wonder the Vietnam War became a trauma not just for those men who served in it but for all Americans of that generation.
     Robert McNamara, who was secretary of defense throughout the period of military escalation, looked back in shame on at least six different failures for which he took at least some measure of responsibility.  There was the failure to consult allies, despite the existence of the Southeast Asia Treaty Organization (SEATO) since 1954;  the failure to appreciate how a people in arms could withstand and overcome the most sophisticated weaponry;  the failure to see the limits of economic and military aid in the process of state building;  the failure to uphold democratic principles in the governance of South Vietnam;  the failure to understand the complex relationship between the application of military force and the achievement of political objectives;  and above all, the failure of the American decision-making process itself.  To explain this, McNamara blamed lack of time, lack of institutional memory within the government, and "the incremental nature of decision making about intervention in Vietnam [which] never allowed policy makers an opportunity to step back."
      Another member of the flagellant order of the former Kennedy-Johnson officials was McGeorge Bundy.  In a memorandum written as late as May 1967—a year after he had left the administration to run the Ford Foundation—Bundy could still assure the president, "The fact that South Vietnam has not been lost and is not going to be lost is a fact of truly massive importance in the history of Asia, the Pacific and the U. S."  Nearly thirty years later Bundy added a simple marginal note; "McGB all wrong."  His explanation for the American failure was a basic underestimation of  "the endurance of the enemy."

-Niall Ferguson,  Kissinger:  1923-1968:  The Idealist