Preface: This article covers over 70 years. It is not meant to be a complete history, just a summary of events as well as a list of sources for further reading / watching so that one can understand how the US and its allies played a part in creating ISIS.
This story starts way back in in 1941 when the US and UK backed coup d'état in Iran after its oil industry was nationalized by a democratically elected leader, Prime Minister Mohammad Mosaddegh. After the US coup the Shah, Mohammad Reza Pahlavi, controlled power within Iran. The Shah turns Iran into a totalitarian dictatorship, until 1979 where he has to run from the country because of a brewing revolution. They say his plane was so full of gold it could barely get off the tarmac. The story continues a few years later with the US flying the Shah around on military aircraft in the US to get surgery. This resulted in the Iranians becoming aggravated enough to take over a US embassy and capture hostages.
You can learn more about that here:
http://en.wikipedia.org/wiki/Mohammad_Reza_PahlaviAt the same time the Shah is being thrown out of power, just one country west in Iraq Saddam Hussein is coming to power. The important things to note are that Iran and Iraq contain a Shia majority. The Iranians install a Shia leader. However Saddam Hussein a Sunni violently grabs power within Iraq. Just a year later in 1980 the Iran Iraq war begins with Iraq being the aggressor. The US backed Saddam, but we will get to that eventually.
http://en.wikipedia.org/wiki/Iran%E2%80%93Iraq_War Skip ahead a few years to 1985 and US Iranian diplomacy is still in shambles and the Iran Iraq ware continues. This is when the Lebanon hostage crisis occurs. To get western hostages back the Regan administration makes some shady deals to sell weapons to Iran, a country that dislikes the US and is on an embargo list mind you. This is known as the Iran-Contra Scandal.
You can learn more about it here:
http://en.wikipedia.org/wiki/Iran%E2%80%93Contra_affairNow what is important to note is that at this point the US had horrible relations with Iran and was beginning to favor Sunnis. So the US threw its support behind Saddam Hussein. They even end up selling him precursors to chemical weapons so he could gas the Iranians, which he did (
http://www.newsweek.com/how-us-nerve-gassed-its-own-troops-then-covered-it-317250). This article is interesting because this came back to haunt the US during the Gulf War when US troops destroyed weapons stores and were poisoned, the cause for “Gulf War Syndrome”, which was subsequently covered up.
Let’s fast forward a bit, Iran loses a lot of its power and influence and its economy is hurt by Western embargoes, Saddam Hussein becomes power hungry, attacks Kuwait, a US oil ally, and gets his ass handed to him in the first gulf war, furthermore Saddam started trading oil in Euros in 2000 and he was supposedly one of major counterfeiters of US dollars (
http://www.theguardian.com/business/2003/feb/16/iraq.theeuro ).
(Commentary: If you are a head of a weak state and have resources don’t piss off the US by trading them in different currencies. They will crush you. Learn more here:
https://www.lewrockwell.com/2006/02/ron-paul/why-the-us-hates-iraq-iran-and-venezuela/ and here were Ron Paul predicted the Libyan invasion:
https://vimeo.com/5372026)