Actually, Hussein and Iraq was a client State of the Soviet Union. Iran was our ally under Mohammad Reza Shah Pahlavi. After Carter turned his back on Reza the Islamic Revolution took off with full steam and the Ayatollah Khomeini came to power and this is what led to what we have today.
I don't get it.
Some of us might remember the good old days of the Iran-Iraq War of the 80's,which pitted Arabs against Persians.
At that time, the CIA,supplied arms to Iran,under Ayatollah Khomeini, and used the profits to secretly fund right-wing Contra rebels in Nicaragua.
On the other side,they also supplied intelligence to the Iraqis and looked the other way when the Iraqi army acquired chemical weapons,with the aid of western firms. These weapons were used against the Iranian army and Iranian population centres and against the Kurds(who were allies of the Iranians), turning the tide of the war in favour of the Iraqis.
The US state department even tried to pin the gas attacks against the Kurds on the Iranians. At the time it seems the US was slightly closer to Iraq than Iran and obviously did not want to get blamed for the proliferation of weapons of mass destruction:
"The U.S. State Department, in the immediate aftermath of the incident, took the official position that Iran was partly to blame. A preliminary Defense Intelligence Agency (DIA) study at the time reported that Iran was responsible for the attack, an assessment which was used subsequently by the Central Intelligence Agency (CIA) for much of the early 1990s. The CIA's senior political analyst for the Iran-Iraq war, Stephen C. Pelletiere, co-authored an unclassified analysis of the war which contained a brief summary of the DIA study's key points. Pelletiere claimed that blue discolorations around the mouths of the victims and in their extremities suggested that a blood agent using cyanide was used in the attack at Halabja, and that only Iran was known to have used blood agents during the war. No proof that Iran had previously used hydrocyanic gas, as asserted by the DIA, was ever presented."
https://en.wikipedia.org/wiki/Halabja_chemical_attack#Allegations_of_Iranian_involvementhttps://www.nybooks.com/articles/1990/11/22/iraqs-chemical-warfare/So,without letting each country get a decisive victory in that war,the US, under Reagan, got two of the most powerful countries in the Middle East to grind each other to dust. And the policy made a lot of strategic sense. If either did achieve total supremacy over each other, they could end up being an existential threat to neighbouring Israel or the strategic Arabian peninsula,with its massive oil and gas reserves.
That's what most people now don't get. Didn't the 2003 invasion ,with the destruction of the Iraqi Ba'ath party and the end of Sunni minority rule in Iraq, simply hand over Shiite-majority Iraq to Iran and ,so, allow Iran to potentially dominate the Middle East?
It seems the exact opposite of the cynical but effective US policy ,of the 80's.