This is a great question, and David R. Henderson’s answer is what I would say. The only difference is, I am less confident that it is right, as compared to David’s apparent confidence. Here’s what he said:
[W]as the second war against Iraq about oil?
In a sense it was, and in a sense it wasn’t.
Here’s the sense in which it was. Various important participants seemed to havethought that it was. Virtually all involved, will, I think, grant that Vice President Dick Cheney had a large influence on the decision to invade Iraq. Here is David Frum’s recollection of part of Vice-President Dick Cheney’s thinking:
In 2002, Chalabi joined the annual summer retreat of the American Enterprise Institute near Vail, Colorado. He and Cheney spent long hours together, contemplating the possibilities of a Western-oriented Iraq: an additional source of oil, an alternative to U.S. dependency on an unstable-looking Saudi Arabia.
So, for Cheney, oil does seem to have been an important factor in his support of the invasion.
But you can do something with motive x even if motive x doesn’t make sense. Which brings me to the sense in which the war wasn’t about oil: From a narrowly selfish point of view, it didn’t make sense to fight war for oil. Here’s where economics kicks in. There is a world market for oil. There is no danger that a country that wants to keep the United States from getting oil can do so simply by restricting sales to the United States. The reason is that it will then want to sell its oil elsewhere. That means that someone who buys that newly freed-up oil will then want to buy less from his suppliers. Those suppliers then have oil to sell and Americans can buy that oil. It’s a game of musical chairs in which the number of chairs equals the number of players. The game would be awfully boring, but in international trade, boring is good.
The only way a country’s government can hurt the United States using the “oil weapon” is to reduce its own production. But then, that country, unless it produces a huge amount of the world’s supply, will hurt itself as well. And that country will hurt its oil-consuming allies and help its oil-producing enemies. I’ve laid this all out in “Do We Need to Go to War for Oil?”
Now, it’s possible that Cheney, Bush, Abizaid, et al were a bunch of economic illiterates. So, again, in that sense, the war could have been about oil even if it didn’t make sense to be about oil.
As I said, if you ask me my opinion, I would give the above answer. But, it seems undeniable that the reason “we’re over in the Middle East” is oil. In general, when people ask me, “Are the people running the government stupid or evil?” I give the cute answer, “They’re not stupid.” So I am a little uncomfortable saying so casually, as David implies here, that the whole foreign policy of the United States is based purely on basic ignorance of economics. I wonder instead if there is an even more nuanced middle ground, whereby it makes sense (say) for a power-hungry group to want to “control” oil, even if that doesn’t translate into lower pump prices for American motorists (for whom they care not a whit).
I am confident David and I are right on the general economics of what’s good for American consumers and how to keep oil prices low, but I’m not sure we should assume governments are trying to ensure the free-flow of oil to their citizens. I could imagine strategic reasons involved that make it valid to say (from their point of view), “We need to put in a friendly government here, to ensure our uninterrupted access to such-and-such resources.”