I think, as I've talked about some on Deano's thread concerning evil, that Anatol Lieven has absolutely nailed what's going on in the U.S. in his book America Right or Wrong, ably summarized by Linda Colley of Prospect magazine here.

As obnoxious as it may seem to the rest of the world, however, it may be better for all of us that massive anti-war protests have not erupted from the left wing.  Beginning with Reagan, the right wing has successfully reconstructed reality, projecting our loss in Vietnam  as the result of a left wing, anti-war, home-front stab-in-the-back to U.S. military power and defense ability.  If they could add further fuel to that fire through present day antiwar activities, it would likely feed further growth of U.S. nationalism, much as the German army stabbed-in-the-back theory fed the rise of the Nazis.

Losing disgracefully would probably, as Jerome pointed out, help to bring Americans back to their senses.  The realization that we are losing is sinking in now, Bush's ratings are plummeting, and of course, that's why Rove has geared up his blame-the-liberals routine.  

But the country needs more than that.  A huge majority thinks there's nothing wrong with Guantanamo.  We are talking serious evil here when people, not just their power-mad government, think that it's ok to do wrong to others because it's just maybe possible that some of them have done wrong to you or helped others who did.    I do not see in either party the kind of mature, morally credible leadership it would take, IMO, to   get that majority to deal with this godawful truth about themselves.