Given the military and rhetorical buildup over the past couple of months, it was evident that the United States would lead a "coalition of the willing" against the Islamic State in Syria. It was not fully clear initially who the United States would partner with and how the alliance would affect the regional, geopolitical and sectarian struggle. Compared to Syria, the fight against the Islamic State in Iraq has been much simpler.
Limited U.S. Choices
Considering their enmity, the United States and Iran could not join forces formally against a common foe. However, this did not prevent them from coordinating efforts behind the scenes. Both were operating through the same local partners — the Shiite-dominated federal government in Baghdad and the Kurdish Regional Government in Arbil — thereby facilitating their efforts in Iraq. In other words, Washington and Tehran agreed upon a system that also had domestic and international support, including Saudi Arabia's, since the Islamic State poses a more immediate threat to Riyadh than the ongoing Saudi rivalry with Tehran.
While efforts against the Islamic State continue in Iraq, there is international consensus that the jihadist movement cannot be defeated there unless it is simultaneously dislodged from Syria, where it enjoys strategic depth. However, the geopolitical situation is such that there is no consensus on how this war is to be waged. Ideally, the natural U.S. allies against the Islamic State would be Iran, the Syrian regime and Hezbollah, who share the U.S. interest of neutralizing the jihadists.
Since it has been cooperating with Iran regarding Iraq, it would not have been difficult for Washington to extend that cooperation to Syria. However, the situation in Syria prevents this. Washington cannot join forces with Damascus, which has waged a civil war that has killed more than 200,000 people. Neither could it partner with Hezbollah, an organization that the United States has declared a terrorist group, has killed U.S. diplomats and servicemen and continues to fight the United States' close ally, Israel. This means Washington had no choice but to side with the Syrian rebels, which required working with their regional patrons: the Arab states, led by Saudi Arabia.
Other factors led to aircraft from Saudi Arabia, Jordan, Bahrain and the United Arab Emirates, with support from Qatar, joining U.S. aircraft in the first wave of airstrikes against the Islamic State in Syria. Washington's European allies, given their own domestic compulsions, decided not to participate in the strikes (though France has been involved in such action in Iraq). Far more important, the United States' only NATO ally in the region, Turkey, is trying to prepare to deal with the messy implications of the war and is not participating in the coalition against the Islamic State.
Iran's Perspective
While certainly pleased that its main long-term regional competitor and historical rival in Turkey is staying out of the fighting, Iran is concerned that this anti-Islamic State effort will lead to further rebellion in Syria. Tehran wants the Islamic State weakened in Syria to the extent that it cannot threaten its satellite, Iraq. However, it also benefits from the Islamic State's presence as a key element in the Syrian rebel landscape, because it prevents the rebels from focusing their attention against Tehran's ally, Damascus. Iran's strategic planners predict that while the Islamic State will suffer serious losses, it will not be uprooted. Any vacuum created will only exacerbate the struggles among rebel groups. Those referred to as "moderate rebels" are a conglomeration of competing factions, including Salafist-jihadists not far removed from the Islamic State. Tehran is betting that the Islamic State will not be eliminated as a player and that other, similar groups will shatter the U.S. perception of "moderate rebels," and with it, U.S. desire to get involved in the rebellion.
Iran's calculations cannot be dismissed as the wishful thinking of a player feeling vulnerable because of the military efforts in Syria. The United States has been apprehensive of seeking regime change in Syria in the event the country becomes another Afghanistan — one in the heart of the Middle East. Even as it seeks to support anti-Islamic State rebels, Washington is not committed to a complete collapse of the current order in Damascus.
For this reason, the United States knows it eventually will have to bring Iran into the equation. Even after Iran's Supreme Leader, Ayatollah Ali Khamenei, categorically refused to cooperate with Washington against the Islamic State, U.S. Secretary of State John Kerry said that Washington was prepared to talk to Tehran about the Islamic State on the sidelines of nuclear talks taking place in New York. Until now, Washington has opposed using the nuclear talks as a venue to discuss any other issues.
While talks continue with the United States, Iran will be busy on other fronts as well. Tehran can be expected to exploit Ankara's fears of the military effort against the Islamic State. The Iranians also have been occupied with bilateral dealings with their main regional enemies, the Saudis, on the Islamic State and on the rise of the Iranian-aligned al-Houthi movement, which has emerged as the single most coherent force south of the Saudi border in Yemen.
Regarding Syria, the Iranians will not simply rely on U.S. fears of jihadists. Tehran will be focusing on the battlefield there to prepare for any situation in which the current regime is once again on the defensive against the rebels as the Islamic State weakens. But from the U.S. perspective, there is no one side in this complex war.
