Although most Americans tend to assume that the U.S. and Iran will be on opposite sides on every issue across the Middle East, in Iraq, that has often been untrue. In the early years after the U.S. invasion of Iraq, Iran was actually very helpful to the United States: Iran did not support the militias and insurgents, and instead it encouraged its Iraqi allies to go along with the American project of building a democracy there, probably because Tehran feared an open confrontation with the U.S., feared Iraq descending into chaos and civil war, and recognized that any Iraqi democracy would inevitably be dominated by the Shi’a, who would probably be on reasonable terms with Iran. Of course, once Iraq slid into civil war, Iran changed gears and backed both all manner of Iraqi militias and supported attacks on Americans to try to get the U.S. troops out of the way. But that change really did not occur until late 2005 or even early 2006, and before then Iran seems to have seen its interests as effectively aligned with our own.

The same seems to be true today. According to various Iraqi sources, Iran believes that it has its hands full with Syria and does not want to open up another front in the region-wide Sunni-Shi’a civil war that many Sunni extremists are now preaching. The Iranians apparently recognize that they are not benefitting from fears of a wider Sunni-Shi’a war and are trying to prevent one from emerging— which is precisely what would happen if civil war resumed in Iraq. Moreover, Tehran no doubt recognizes that a civil war on its doorstep would be particularly dangerous because the spillover could easily affect Iran’s own fractious minorities and fragile internal politics.

Other Iraqis report that Tehran sees a new civil war in Iraq as being potentially deleterious to its currently enviable position within Iraq. Unless the Shi’a could win a quick, overwhelming victory in a new civil war, the status quo is preferable to any other outcome for them. In any other scenario, Iraq would be torn by fighting and the Shi’a dominated government would likely lose control of parts of Iraq. Much better, from Tehran’s perspective, to have the Shi’a in nominal control over the entire country— in part to enable Iran to move supplies across it to their allies in Syria.