Iraq as Vietnam: history repeats

See if this excerpt from The March of Folly doesn't give meaning to the saying that those who don't learn from the past are doomed to repeat it.

Ignorance was not a factor in the American endeavor in Vietnam pursued through five successive presidencies, although it was to become an excuse. Ignorance of country and culture there may have been, but not ignorance of the contra-indications, even the barriers, to achieving the objectives of American policy. All the conditions and reasons precluding a successful outcome were recognized or foreseen at one time or another during the thirty years of our involvement. American intervention was not a progress sucked step by step into an unsuspected quagmire. At no time were policy-makers unaware of the hazards, obstacles and negative developments. American intelligence was adequate, informed observation flowed steadily from the field to the capital, special investigative missions were repeatedly sent out, independent reportage to balance professional optimism - when that prevailed - was never lacking. The folly consisted not in pursuit of a goal in ignorance of the obstacles but in persistance in the pursuit despite accumulating evidence that the goal was unattainable, and the effect disproportionate to the American interest and eventually damaging to American society, reputation and disposable power in the world.

The question raised is why did the policy-makers close their minds to the evidence and its implications? This is the classic symptom of folly: refusal to draw conclusions from the evidence, addiction to the counter-productive.