Lesson #2: It’s not that hard to hijack the United States into a war. The United States is still a very powerful country, and the short-term costs of military action are relatively low in most cases. As a result, wars of choice (or even “wars of whim”) are possible. The Iraq war reminds us that if the executive branch is united around the idea of war, normal checks and balances — including media scrutiny — tend to break down.