Defeat in war damages societies quite out of proportion to what a rational calculation of cost would predict. The United States absorbed the loss in Vietnam quite easily on paper, for example, but the societal effects of defeat linger to this day. The Afghanistan debacle was an underrated contributor to Soviet malaise in the 1980s and a factor in perestroika, glasnost and eventually the dissolution of the Soviet Union. Defeats can have unintended, seemingly inexplicable consequences.
Or so says Prof. Fettweis of the Naval War College (he's apparently something of a "military strategy wonk" there). I've noted on a number of occassions that whetever else this war brings it will surely be one of the dominant themes of American politics for a generation. Which I think is rather unfortunate, since it is likely that its dominance will be more about fingerpointing than any actual discussion of the war itself. Which is why we need to take Prof. Fettweis' advice seriously (though I doubt that we will):