Following the end of the Vietnam War, journalists and historians spent the next 25 years trying to explain why America had been drawn into a war "it couldn't win" and why it had been so reluctant to admit this unassailable realization.
The lesson of Vietnam was that, short of employing "weapons of mass destruction" it was unlikely we could overcome an indigenous revolutionary army through the usual ground offensive tactics, especially in the tangled terrain of tropical Southeast Asia. America's failure there, and our open admission of that failure, left a festering scar on our national pride. We had made a big commitment to "liberate" a nation, to preserve its possible future as a model Western-style democracy, but we had utterly failed, in large part because we had ended up nearly destroying a country we were trying to "save." Our indiscriminate use of Agent Orange, "cleansing" the countryside village by village of embedded Viet Cong volunteers, our pragmatic support of a corrupt puppet regime, the killing of hundreds of thousands of blameless civilians--these were the consequences of our adventure in Indo-China.