Most of our oil comes from Canada and South America.
Incorrect. Canada is number 1, the Persian gulf is number 2. Mexico is the second largest individual country - just ahead of Saudi Arabia.:
U.S. Imports by Country of Origin But even that doesn't matter, because we buy oil on the global market just like everyone else does. We don't get "cheap" oil from Iraq or anywhere else. We also don't really do much to "ensure free availability of oil" - hell, we even refuse to "buy" Iranian oil.
Do you really think we don't want Iranian oil on the world market??
Our mideast policy is all about ensuring access to oil. Our confrontational stance with Iran is all about our alliance with the House of Saud and Israel. Sunnis versus Shiite versus Jew. A complicated mess. But if there was no oil in the Mideast we would not have spent the trillions we have on military and foreign aid to the area over the past 50 years. Do you really dispute this? Are you old enough to remember the 1970s?
As for the "petrodollar", it doesn't have much if anything to do with the military - at least not directly. What other currency is a producer/buyer/investor going to use? The Euro? Too new, too fractioned, too unstable. The Ruble? Same problem, times a million. The Dinar? Riyal? Hrivna? Yuan? If one looks at the world currencies, stability, liquidity, ease-of-use and every other metric associated with a currency, one would be an abject fool to want to use anything but a dollar.
Well, don't take this the wrong way but based on the above you don't seem to understand how the global energy market functions or how having the world's reserve currency works. You ask what other currency would they use? but the question is why must they use the USD and what is the advantage to the US that they do use it ? It a large topic but well beyond what is appropriate for this forum but a few points of fact:
By Oil being priced in dollars we are able to buy it at any price with money we create out of thin air. We can run a large trade imbalance with little consequence (for now). No other country can do that.
In 2000 Iraq converted all its oil transactions under the Oil for Food program to euros. After the U.S. invaded Iraq in 2003, it returned oil sales from the euro to the USD
In 2007 Iran began trading oil with the newly constructed
Iranian Oil Bourse In 2006 Venezuela supported Iran's decision.
The connection of the above to geopolitical events should be obvious.
Look, the US is doing the same thing every other Empire has done throughout history: Using it's military and economic power to control it's access to resources. Oil and gas are the most important global resources necessary to drive any modern economy. Part of this control requires reserve currency status.
Before us the British, the Dutch, the Spanish, the Portuguese, the Romans, etc, etc have all done the same thing- used a combination of military strength and
Neocolonialism to try and expand and maintain their empires.
This is not even something that is remotely controversial among historians or foreign policy experts.