After several recent high-level political and military meetings between Turkey and the United States, the two countries appear to have settled their differences. In recent weeks, Turkey has moved considerable forces south, closing off the final sections of its border adjacent to Islamic State positions in Syria. In addition, Ankara finally opened Incirlik air base — and possibly other air bases for primary or emergency use — to U.S.-led coalition aircraft. Moreover, Turkey began carrying out its own airstrikes against select Islamic State positions in Syria.
As well as sealing the border, internal security forces began rolling up Islamic State networks (and Kurdistan Workers' Party militants) in Turkey. The timing of these actions suggests that Ankara is expecting a backlash from the jihadists. Once Turkey decided that actively combating the Islamic State was in its best interests, it wasted no time to act. By negotiating a deal with Washington that involves working proactively against the Islamic State, Ankara will have to accept the consequences. That anticipated backlash manifested in a recent car bomb attack not far from Kobani and a border clash between the Turkish military and the Islamic State. But so far, the retaliation has been relatively limited.
The Impact in Syria
Though exact details of Ankara's deal with Washington are still emerging, there is no doubt that increased Turkish involvement will have a significant effect on the war in Syria.
First and foremost, the Turkish military moving to secure the border sections abutting Islamic State positions in Syria should seriously degrade a vital logistical line for the Islamic State. The jihadist group has consistently been embroiled in fighting along the entire periphery of the territory it carved out last year. This uncompromising strategy allowed the Islamic State to expand aggressively, but the jihadists have stagnated overall and are now on the defensive in many areas. Defending proved to be an unexpected drain on Islamic State resources, at a time when they are already taking heavy losses.
Although the Islamic State was able to gain much during its rapid expansion, including captured military materiel, the group also relied heavily on extended supply lines. These lines allowed the Islamic State to exchange captured resources — such as oil and historic artifacts — for weapons and equipment as well as money to pay its fighters. The supply lines also kept a steady stream of foreign fighters coming in to replenish the Islamic State's ranks, which allowed it to sustain a high attrition rate. Cutting off the supply line through Turkey will hit the Islamic State hard on all fronts, especially as the effects of the cutoff accumulate over time.
The opening of Turkish air bases makes the air campaign against Islamic State positions in Syria massively more efficient. The previous distances involved for U.S.-led coalition aircraft from various locations in the lower Arabian Peninsula ensured mid-air refueling and longer flight times. Greatly reducing the distance from takeoff to targets in northern Syria gives the coalition more options. These include varying weapons payloads, sortie rates, the number of aircraft that can be on station and, most important, persistence over enemy territory that will improve responsiveness, intelligence and situational awareness. In short, the air campaign will become easier to conduct in this region and can be greatly expanded if needed. But, it will not become more effective unless the coalition increases surveillance coverage and trained air controllers on the ground.
The increased threat to Islamic State territory in both Syria and Iraq is not lost on jihadist commanders. Much of the group's success depended on the quick movement of forces and materiel between theaters. The fracturing of supply lines degrades this capability over time. And it will only get worse. The air campaign's greater reach into northern Syria will inevitably degrade Islamic State forces overall, pinning some elements in place. Improved loiter time also means less sanctuary for high-value targets; hunted by increasingly effective air assets. In turn, these effects are likely to impact the Islamic State's command and control.
Turkey's policy change toward the Islamic State solves two problems at once. Turkey's primary focus was on removing the al Assad government in Syria and avoiding a full-scale fight with the Islamic State. This kept domestic security relatively stable early on in the Syrian conflict. But the Islamic State's expansive territorial growth and aggressiveness toward other rebels (including many Turkish-backed groups) eventually became intolerable for Ankara. Taking military action against the Islamic State should eventually bring relief for the northern Syrian rebels fighting both the Islamic State and Syrian government forces. This brings U.S. and Turkish interests into alignment, and Ankara likely hopes that the degradation of the Islamic State will lead to a coherent rebel force that can focus solely on Syrian government forces. The cost of Ankara's policy change, however, is that the Islamic State will strike back. Some attacks on Turkish soil have succeeded, but internal security forces are working hard to mitigate their effectiveness, and Turkey has the force structure and experience to handle internal militancy.
Quid Pro Quo
As with any deal, there is reciprocation. Turkey has given the United States what it wants to fight the Islamic State, but Washington has made concessions of its own. These likely involve greater support for Turkish-sponsored rebel factions in northern Syria. The issue of reciprocity raises a series of questions about what other changes might occur in the ongoing fight.
Rumors emerged recently that Turkey could send in a full-scale military force to create a buffer zone that would displace the Islamic State (or any Syrian regime forces) and serve as a safe space from which rebel factions could project power. Technically, the actions Turkey has already taken could accomplish this in a longer time frame, but success is not assured and Turkey's patience is being tested. The main question would be how Turkey's domestic population would receive the establishment of a buffer zone. Turkey is very politically divided, and any overt Turkish military moves could conceivably overlap with Ankara's Kurdish conundrum. Turkey is frustrated by the amount of positive press the Kurds received as the only trustworthy or effective force fighting the Islamic State.
The Turkish military has already moved the appropriate force structure into place to establish a buffer zone. A likely indicator that Turkey is establishing the safe area would be a significant increase in aerial and artillery bombardment of Islamic State positions abutting the Turkish border, though such action might not be necessary. Turkey has a variety of levels of involvement to choose from in pursuit of a buffer zone, from no-fly zones to the manipulation of rebel forces — using the talents of embedded special operations forces. Turkish daily Hurriyet reported July 24, citing anonymous sources, that a partial no-fly zone over the Turkish-Syrian border would be part of the broader U.S.-Turkish understanding. The volume and location of airstrikes should be carefully monitored and reports of forces embedded with rebels should be closely watched.
A change in U.S. policy toward support for northern Syrian rebels should also be looked for. Currently, the United States is striking only the Islamic State in Syria, and the train-and-equip mission it is pursuing to create the New Syrian Force is intended to focus on the fight against the Islamic State. Potentially, Washington could soften its restrictions on this support. The first few troops for the New Syrian Force entered Syria recently. Newly arrived U.S. coalition air power could be an excellent force multiplier for any ground troops in the vicinity. Any sign that such air power — or the U.S.-trained New Syrian Force — is being woven into Turkish-backed rebels could point to a U.S. policy shift. Additionally, U.S. airpower, especially through operations out of Incirlik, could facilitate any of the buffer zone options that Turkey is contemplating.
In the longer term, Turkey's new policies could lead to real military success — not only against the Islamic State but also against the Syrian government. This raises the question of whether rebel political coherence and structure will accompany military coherence and success. A dominant and somewhat coherent rebel faction that can assume responsibility given a political resolution to the conflict is something important to look for in context.
For the al Assad government, Turkey's shift should be alarming. Although Ankara is expanding its focus to include the Islamic State, this change will help the other Syrian rebel factions, and eventually all paths lead back to Damascus. The United States, on the other hand, will try to use the added military pressure on the Syrian government to push for a negotiated settlement. With the momentum behind the rebels and their sponsors, however, U.S. — and Russian — efforts to fashion such an agreement will be highly conflicted. This is the risk that the United States is willing to take in order to clamp down on the Islamic State.