Okay, I'll go along with the Oil conspiracy theory, and construct why this concept why it doesn't work in the most simplified form.
It begins, a barrel of oil doubles in price from certain regions. Well, first off, they aren't the only oil supplier in the world, if they want to hold those prices hostage to us, they wont make much money for long before having to lower their prices again. This will happen due to growing their supplies, and having nowhere to store it. The goods become liquidated, and purchasers/investors/speculators become very weary of doing business with them in the future.
We invade those regions. Now we miss seeing a market correction, we spend extra money anyways and cost lives in the process, and on top of all that, our relationship is weaker with them, therefore they STILL don't lower prices to the true market level.
We lose on oil prices, we lose on having a good trade relation, we lose a lot of lives, and we burn up a lot of oil in the process! There is no way that we protect oil prices by doing what we are doing.
It is immoral to hold their natural resources hostage to them. It is immoral to bomb them, injure them, kill them, as well as kill and injure ourselves. It is immoral to give them money for the sake of building things that are destroyed by it's own people. It is also immoral to steal this money from so many Americans who disagree with war for whatever reason.