My main problem is that people don't really think through what it means to be "for oil."
The war was undoubtedly fought "for oil" in the sense that oil was the primary interest of the United States. But what, exactly, does that mean?
There's a conception that the U.S. was just going to "take" the oil, or seize "lucrative oil contracts." Both arguments are, in my opinion, fucktarded. The US was never going to "take" the oil, and the implication that the war was entirely about something which the U.S. then didn't actually do is just too stupid for words. People who maintain this argument usually claim the U.S. was going to take the oil "except" something stopped it ("the public found out etc"), which is such a foolish argument I can't be bothered to address it.
Second, and slightly more sophisticated, is that the war was about oil contracts. Two blatant problems with that argument. First, oil exploitation contracts are incredibly unprofitable relative to the cost of the war. It would have been like investing $1000 to make a $1. Second, the bidding was open, and French and Brits and Chinese profited as much or more than the Americans. This theory thus requires some explanation about why the US embarked on a ludicrously unprofitable war, and the answer is usually some epic corruption story -- Halliburton doesn't care, it will spend $2 trillion in taxpayer money to make $20 billion for itself, muhahahah!
Again, super-stupid.
Far and away the strongest oil explanations are those which view the situation as an *oil supply threat* that the US set out to resolve. The international economy is critically dependent upon a continuing supply of oil, largely Middle Eastern in supply. Saddam's invasion of Kuwait demonstrated how vulnerable that supply was to political intrigues in the Middle East. It was crucial to establish control over the oil production system to get constant supply to the international markets. This ensures that the price is reasonable and the global economy is not hammered by oil shocks. Thus the key was never stealing oil, or making money on contracts. It was putting in place a system of political control that ensures the Middle East "plays nice" with the United States on oil production policy.
Put very short, the war was all about converting Iraq into Saudi Arabia. We don't steal Saudi Arabia's oil, and we don't make appreciable money on Saudi oil contracts. Yet because it works with us on ensuring the total global oil supply is workable, Saudi Arabia is arguably our most important ally -- or was, until fracking made the US oil independent. IMO, the Iraq War would never have happened after the rise of fracking made the U.S. so much less dependent on continuous ME oil supply.