That makes even less sense. Are you really saying that the U.S. invaded Iraq to control China's oil supply? Again, neither the numbers nor the facts support your assertion. The numbers suggest that China is getting all the oil it wants from Iraq even if America is not. The political situation in Iraq is characterized by America giving up authority to Iraqi officials as soon as the security, bureaucracy and infrastructure conditions allow. As indicated in the link I gave you, Iraqi oil exports are controlled by an Iraqi state committee for it's own benefit. There is no indication that the U.S. is controlling the production or distribution of their oil. No doubt the U.S. is still protecting and defending Iraqi oil facilities but you can think of that as the modern interpretation of the Marshall Plan, i.e. support the economic and national security efforts of the defeated nation so that it can rebuild a stable economy and rejoin the international community with the dignity and respect of an equal on the international stage.
Simply pointing out that it was one of many bad reasons the Bush Administration took us to war. First it was because of 9/11; then because they have WMD; then because we're spreading democracy, blah, blah, blah... The justification for the war was a bunch of little things added up and oil was a larger-than-average piece. Most of the world knew the U.S. evidence was weak, it's a shame the public didn't know. They simply swallowed the propaganda and the same people now are whining about getting out.
Let's use a hypothetical. Country A accounts for a significant portion of the U.S.'s oil, but has a volatile history with China. China starts seeing threats where they don't exist and brings evidence to the world. The world rejects the evidence as paranoia. China decides it can't live with this threat and invades. China claims it will turn the country over when it feels things are safe. Even if it's true, I doubt anyone in the US would feel comfortable with this situation. We didn't even feel comfortable when Russia invaded a small country like Georgia. We often believe in this country that what we say is taken as the truth around the globe and that simply isn't the case as so many are skeptical of the US especially after the last eight years. Control isn't just direct control, but political influence, indebtedness all fall under the umbrella.
I also want to point out that war isn't always about facts and figures. It sometimes happens for the stupidest of reasons as history has shown.
I want to get back to the whole German economy. The premises I see are that Germany's economy was thriving and Germany instituted several economic policies many consider socialist. It has been suggested that this prosperity was illusionary and the Germans were going to use plunder to keep it alive. I can understand using plunder to fund the war machine similar to how the Romans did 2,000 years ago, but I don't recall seeing any evidence that the Germany economy was straining prior to the war. Although, I admit I haven't look that carefully at this. Since you have a history degree, you'd have a better idea than I.