That's not the lesson Americans should learn from this forever-war disaster. The lesson everyone should be learning is that America's founding heritage of non-interventionism is the way to go in the future. 

In other words, rather than engage in "smart" interventionism, as the interventionists will advocate, America should engage in no foreign interventionism whatsoever. That would mean that the United States would bring all of its troops home from overseas and discharge them. It would mean abandoning all U.S. military and CIA bases and installations in foreign lands, including the U.S. torture and prison camp at Guantanamo Bay, Cuba. It would mean no more interventionism in foreign lands, including invasions, wars of aggression, coups, alliances with dictatorial regimes, and foreign aid. 

This is what Americans should be discussing and debating going forward. Rather than focusing on the "mistakes" that led to the Afghanistan debacle, Americans should raise their vision to a higher level, one that challenges the overall concept of foreign interventionism itself.