In 10 sentences or less…
OPEC is an international cartel made up of 12 countries (6 middle-eastern, 4 African, and 2 South American) and controls about 2/3 of the world’s oil.
The chosen currency of OPEC has traditionally been the US dollar and amounts to a large portion of US dollars in circulation (basically, the currency is in circulation strictly to accommodate the oil trade and can’t be successfully backed by other US assets).
In the years preceding the war, OPEC began voting to switch trade currency to another currency, which would leave trillions of dollars held by other countries for oil worthless.
Nearly all of the Muslim OPEC countries voted for the immediate shift but lacked the majority vote until Venezuela decided to tip the vote.
By overtaking Iraq, which was a threat in many other ways, and which was strategically positioned in the heart of the middle east, the US was not only able to greatly diminish Jihadist activities around the world, but also to stop the majority vote needed to shift currencies from the USD to the EURO.
Imagine the insane inflation and anger of the world when it suddenly needed to exchange dollars for euros – the euro would become very expensive (benefitting the European Union) and would drive the value of the dollar into the dirt (causing foreign USD investors to be more than pissed at the US).
Instead of having just the Middle East against us, we’d have China, Asia, Russia, India, etc. because their hard-earned dollars suddenly wouldn’t be able to buy them anything, which would spark another world war against the US.
Switching the dollar would also mean insanely high prices and instant poverty to Americans trying to buy stuff with their worthless dollars.
Besides taking over Iraq and freeing its oppressed people, we also launched an economic attack against OPEC which consisted of buying up oil at an alarming rate (which also drove up the cost of oil) which greatly depleted OPEC’s oil supply.
OPEC basically ran out of oil to sell and had to cut production at about the time the market crashed in the US, which not only caused terrorist countries to run out of funding for terrorist organizations, but caused the US to have an excess oil supply which drove down oil prices in the US.
There, my 10 sentences are up. Now that you understand that, I’ll go ahead and tell you that this is only one aspect of the war, and that GW Bush and cronies are actually the smartest and most advanced military and economic geniuses ever to have held office in the history of our country. Not only is the Jihadist movement mostly crushed, but the world has realized how important the US is to the world economy, a middle-eastern country is now a US ally and has religious and political freedom, OPEC’s power has largely been stripped from them, and less than 10,000 US lives have been lost in a war that has lasted six years.