Heck of a job, Barry.

While Washington focuses on Iran-U.S. nuclear talks, the Islamic Republic is making a major but little-noticed strategic advance. Iran’s forces are quietly occupying more of Iraq in a way that could soon make its neighbor a de facto Shiite satellite of Tehran.

That’s the larger import of the dominant role Iran and its Shiite militia proxies are playing in the military offensive to take back territory from the Islamic State, or ISIS. The first battle is over the Sunni-majority city of Tikrit, and while the Iraqi army is playing a role, the dominant forces are Shiite militias supplied and coordinated from Iran. This includes the Badr Brigades that U.S. troops fought so hard to put down in Baghdad during the 2007 surge.

The Shiite militias are being organized under a new Iraqi government office led by Abu Mahdi Mohandes, an Iraqi with close ties to Iran. Mr. Mohandes is working closely with the most powerful military official in Iran and Iraq—the Iranian General Qasem Soleimani, the head of the Quds Force of the Revolutionary Guard Corps. Iran’s official news agency last week confirmed Western media reports that Gen. Soleimani is “supervising” the attack against Islamic State.

This is the same general who aided the insurgency against U.S. troops in Iraq. Quds Force operatives supplied the most advanced IEDs, which could penetrate armor and were the deadliest in Iraq. One former U.S. general who served in Iraq estimates that Iran was responsible for about one-third of U.S. casualties during the war, which would mean nearly 1,500 deaths.

Mr. Soleimani recently declared that Islamic State’s days in Iraq are “finished,” adding that Iran will lead the liberation of Tikrit, Mosul and then all of Anbar province. While this is a boast that seeks to diminish the role of other countries, especially the U.S., it reveals Iran’s ambitions and its desire to capitalize when Islamic State is pushed out of Anbar province.

The irony is that critics long complained that the U.S.-led invasion of Iraq in 2003 created a strategic opening for Iran. But the 2007 surge defeated the Shiite militias and helped Sunni tribal sheikhs oust al Qaeda from Anbar. U.S. forces provided a rough balancing while they stayed in Iraq through 2011. But once they departed on President Obama’s orders, the Iraq government tilted again to Iran and against the Sunni minority.

Like it or not, the presence of US troops in what were hostile and dangerous countries has been a stabilizing force for those countries. See: South Korea, Japan, Germany. Obama’s precipitous withdrawal of US troops from Iraq (along with his continued degradation of US military readiness) is reminiscent of the Democrats gutting of the Paris Peace Accords that lead to the fall of South Vietnam.

While Islamic State must be destroyed, its replacement by an Iran-Shiite suzerainty won’t lead to stability. Iran’s desire to dominate the region flows from its tradition of Persian imperialism compounded by its post-1979 revolutionary zeal. This week it elected hardline cleric Ayatollah Mohammad Yazdi to choose Iran’s next Supreme Leader.

The Sunni states in Turkey, Saudi Arabia, Egypt and the Gulf are watching all of this and may conclude that a new U.S.-Iran condominium threatens their interests. They will assess a U.S.-Iran nuclear deal in this context, making them all the more likely to seek their own nuclear deterrent. They may also be inclined to stoke another anti-Shiite insurgency in Syria and western Iraq.

All of this is one more consequence of America leading from behind. The best way to defeat Islamic State would be for the U.S. to assemble a coalition of Iraqis, Kurds and neighboring Sunni countries led by U.S. special forces that minimized the role of Iran. Such a Sunni force would first roll back ISIS from Iraq and then take on ISIS and the Assad government in Syria. The latter goal in particular would meet Turkey’s test for participating, but the Obama Administration has refused lest it upset Iran.

Really now, who are the traitors?

iran isis