A couple of comments stood out for me. One was this:

there is a danger that we won't learn the right lessons, particularly related to the limitations of our power.
That danger seems very real to me, and in that sense it might be a good thing if the specters of Iraq and Afghanistan haunt us for a good while. If the haunting reminds us that while force can remove a government, it cannot make a new one or build a nation, it will at least serve some purpose.

I also noted this:

"We think it is about us, and it is about our security. But in the end, it is about their politics … success in Iraq was always going to be defined by politics. We needed a political solution, a pact, a peace."
and I couldn't help noting the "we". Yes, we needed a peace. Arguably the Iraqis needed or need the same. You could say the same about the Afghans. That doesn't mean a pact or a peace will come any time soon, or that we can make one happen. IMO, of course... but realistically, when external force removes a government, there's a power vacuum. That vacuum is filled by the removing power, or local powers will fight to fill it themselves. The ideal solution, for us or for the people, might be a peaceful agreement between all of those parties. Whether or not we can bring that ideal solution to pass is another question altogether, one that must be realistically assessed before we decide to create the vacuum in the first place.