A commentator on NPR (Scott Simon, I think) took some pains to explain the "Powell Doctrine" of military engagement that has become a kind of benchmark for American thinking about armed conflict. As I understand it, the Powell Doctrine states that America should only engage an enemy when we are certain that our force is overwhelming; that we should only engage when the entry points are secure; that we should have absolutely clear goals; and that we must be certain of a safe exit.
While I certainly admire Secretary Powell, it seems to me that his doctrine applies only to the nation that we ceased to be on Sept 11. The historical truth of the matter is that nations are compelled to enter armed conflicts without the assurance that their force can overwhelm their enemy's; often with no safe and certain entry point; often with only the most general goal to defeat and disarm the enemy; and with no guaranteed outcome or exit point.
The American colonies did not engage the British empire with any notion of possessing overwhelming force; or knowing what the outcome might be. The same might be said of any war, really. In the perverse way that history often works, the Powell Doctrine only corroborated the circumstances of the Gulf War after the fact. Of course the US Military possessed overwhelming power compared to Iraq's; of course the way in was assured by other Islamic states shocked by the takeover of their neighbor Kuwait; our goal of restoring Kuwait's sovereignty was highly limited (and arguably inadequate in hindsight); and the way out was of our own choosing
Americans should not assume that things are so certain this time.
It is hard not to observe in the blizzard of commentary how America has been afflicted by decades of cultural relativism, and the systematic emasculation of our intellectual classes. Many of the voices I hear would seem to be content if we bombed Afghanistan with teddy bears in the hope that they might be hugged back to liking us more.