I find it hard to imagine that if we had found that Iraq was, say, eighteen months from having a nuclear bomb, we would be seeing the same national debate we have now. If troops had found a decent sized stockpile of uranium, or designs for a bomb, or what have you, the majority of Americans would now think that the war was a good idea, even if all other events had unfolded the same way. Jim and Julian, presumably, still would not. But they would have lost the national debate. ~Jane Galt (Megan McArdle)

Unfortunately, I think Ms. McArdle is right, which tells you a lot about just how little actual argument has to do with our “national debates” and how they are “won.”  This is the anatomy of an American “national debate”:

One side advocates for X with great urgency and warnings of future doom, and the other side lays out all the reasons why X is horrible and foolish.  The first side laughs off all these warnings as fantastic nonsense uttered by the naive or the immoral.  The public pays no attention to the arguments and listens to the fearmongering by the first side, convincing themselves that the people on Side A are decent, upstanding types (not like those maniacs from Side B) who would never steer “us” wrong.  Once X has started and done its damage (whatever that might be), it is only when literally everything that Side A said has been proven false with a vengeance that the public begins to reconsider that Side B might have had a point.  Not that Side B was “right,” mind you, but that they were not quite the band of clowns that the public had taken them to be (at the insistence of Side A).  At this point someone notices that if Side A had been right about anything at all, particularly about one of the potentially more worrisome warnings of danger, the entire “debate” would have swung back to Side A, in spite of their having made a colossal mess of the entire project, because the public still believes that “we” had to “do something.”  This urge to “do something” can only be outweighed by the sheer incompetence with which the government actually does things.  This is small consolation, since the experience of numerous past failures never convinces the public to stop trying to have the government “do something” about this or that. 

The structure of our “national debates” is powerfully and completely biased in favour of unwise, rash policy innovations and against deliberation and patience.  It is also strongly biased in favour of the activists in this or that area of policy, which tends to produce bad results because said activists are typically long on enthusiasm and short on understanding.  They know just enough to know that their policy proposal must prevail, or else all is lost.  More than this, they do not know.