Tyler Cowen linked the other day to a study which showed that countries whose leaders have formal training in economics don't perform better economically than countries whose leaders lack such training.

There are obviously all kinds of reasons why this might be the case, but it's a reminder that, to me, the very most important attribute in a policymaker isn't to have a ton of knowledge about the issues but, rather, to understand the limits of his knowledge. If I were asked to make an important decision about a subject where I knew I didn't know what I was talking about, I would try to survey some informed people, pick out the areas of broad consensus, and try to make a decision based on the idea that the consensus points are true and the others are uncertain. This is a good, if imperfect, heuristic. By contrast, if you're asked to make decisions about some subject where you have a lot of information, you're going to be inclined to push your pet ideas, and your pet ideas are probably wrong.

This is what's so dangerous about things like Bush's notions about Iran. It's be one thing for the president to be ignorant about Iran, the Persian Gulf more generally, energy markets, etc., if he realized he was ignorant. Instead, though, he seems to have convinced himself that his ignorance is some kind of virtue, exhibiting a deeper level of strategic understanding.

We want to hear what you think about this article. Submit a letter to the editor or write to letters@theatlantic.com.