Lesson #1: The United States lost.
Lesson #2: It’s not that hard to hijack the United States into a war.
Lesson #3: The United States gets in big trouble when the “marketplace of ideas” breaks down and when the public and our leadership do not have an open debate about what to do.
Lesson #4: The secularism and middle-class character of Iraqi society was overrated.
Lesson #5: Don’t listen to ambitious exiles.
Lesson #6: It’s very hard to improvise an occupation.
Lesson #7: Don’t be surprised when adversaries act to defend their own interests, and in ways we won’t like.
Lesson #8: Counterinsurgency warfare is ugly and inevitably leads to war crimes, atrocities, or other forms of abuse.
Lesson #9: Better “planning” may not be the answer.
Lesson #10: Rethink U.S. grand strategy, not just tactics or methods.