One thing that I didn't make sufficiently clear--for which I, yes, apologize--is that I'm making a methodological argument about learning, not a play to exclude war opponents from the nation's op-ed pages and blog comments sections. Nor a call to start randomly invading smaller countries in order to find out which ones we can hold. Failure, and how societies handle it, is a topic that I happen to be deeply interested in, so I've done a fair amount of research on it.

Obviously, there are people who were right about the war for the right reasons, and we should examine what their thought process was--not merely the conclusions they came to, but how they got there. Other peoples' opposition was animated by principles that may be right, but aren't really very helpful: the pacifists, the isolationists, the reflexive opponents of Republicans or the US military. Within the limits on foreign policy in a hegemonic power, these just aren't particularly useful, again, regardless of whether you are metaphysically correct.

"It won't work" is the easiest prediction to get right; almost nothing does. The thought process that tells you something probably won't work is not always a good way to figure out what will, even if you were right for the right reasons, as I agree lots of people were. That's why libertarians have a great track record at predicting which government programs will fail (almost all of them) and a lousy track record at designing ones that do work.

On the other hand, "I thought it would work for X reason", when it didn't work, is, I think, a lesson you can carry into both decisions about what to do, and what not to do. On a deeper level, understanding the unconscious cognitive biases that lead smart and well meaning people to believe that things which will not work, will work, is a very good way to prevent yourself from making the same mistake.

America gets a lot of things right, I think, precisely because it includes people who have gotten it badly wrong. Most societies shun people who err; a senior business executive in Germany who has been attached to a failing company should not expect ever to be trusted with responsibility again. America, on the other hand, is a nation of failures, and has always been more hospitable than anywhere else to the people who made an honest mistake, even a lot of them. I believe that our economy works better than our foreign policy process precisely because foreign policy tends to be decided by either the successes or the failures, but never both.

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