Opponents of the Iraq War like to say that all we did by overthrowing Saddam was give Iran a gift. We eliminated an enemy and gave them opportunities to influence Iraq through shared Shia beliefs.
This is hogwash. It also displays a frightening lack of nuance--a quality they claim to uniquely possess.
Iran certainly was happy we defeated Saddam--the man who invaded Iran that led to an 8-year war that killed perhaps 650,000 Iranians in battle (and half that number of Iraqis).
If we did Iran such a favor, you have to ask why the mullahs continued to hate us so. But never mind that.
The fact is, Iran had more means to influence Iraq's Shias when Saddam was in power because Saddam exploited and murdered Shias. Iraqi Shias could be excused for looking to Iran for support given our abandonment of Shias in 1991 after urging someone to rise up and overthrow Saddam. Imagine our surprise when Shias did that rather than the safe Sunni Arab generals we hoped would put a bullet in Saddam's head.
Now, Iraq's Arab Shias mostly see the influence of non-Arab Iranians as interference rather than salvation.
Right now, without US troops on the ground and without a conventional military able to stand up to Iran, Iraqi leaders have no choice but to appease the Iranians at least somewhat while Iran is stronger. As I've mentioned, appeasement is actually a policy that makes sense if you use the time you buy to get stronger rather than thinking of it as a policy to make a foe into a friend.
If Iraq didn't see us as a potential ally, they wouldn't want US weapons which require US friendship to maintain and use. Iraq wants US weapons. Indeed, the Iraqis want them faster:
Iraq's prime minister pressed for faster deliveries of weapons to help arm his country's military during a Thursday meeting with a senior U.S. defense official.
Prime Minister Nouri al-Maliki made the request during talks with U.S. Deputy Defense Secretary Ashton Carter in Baghdad, according to a statement by the Iraqi leader's office.
Al-Maliki said Iraq needs to beef up its defenses to protect the country's security and national sovereignty, and to tackle terrorist groups that continue to threaten Iraq's stability more than nine years after the U.S.-led invasion.
Iran certainly has influence in Iraq. But they are trying to create and exert influence. What's our excuse if we think we don't have enough influence?