While other powers are preoccupied with the fight against the Islamic State in 2017, Turkey will expand its sphere of influence in northern Syria and Iraq, driven as it is by its imperative to block Kurdish expansion. In Syria, the presence of Russian troops will probably prevent Turkey from venturing any farther south than al Bab in northern Aleppo province. From al Bab, Turkey will try to drive eastward toward the town of Manbij to divide and weaken areas held by the Kurds. Turkey will also lobby for a bigger role in anti-Islamic State operations in Raqqa. Turkey will deploy more of its own forces in the Syrian fight, both to obstruct the expansion of Syrian Kurdish forces and degrade the Islamic State.
There are, of course, some drawbacks to Turkey's strategy. Namely, it runs the risk of clashes with Russian and Syrian Kurdish forces. Ankara will thus have to concentrate on maintaining closer ties with Moscow to avoid complications on the battlefield, even as it manages tensions with the United States over Washington's continued support for the Kurds.
In Iraq, too, Turkey will extend its influence in the north — notably, to where the Ottoman Empire's border was once drawn through Sinjar, Mosul, Arbil and Kirkuk. And as it does, it will compete with Iran for influence in the power vacuum left by the Islamic State's defeat in Mosul. Turkey's resurgence threatens Iran's arc of influence across northern Syria and Iraq, and Tehran has plenty of ways it can respond. The government will encourage Shiites in Baghdad to resist what they will characterize as a Turkish occupation. It will also rely on Shiite militias to block Ankara by contesting territory and exploiting divisions among Iraqi Kurds. Saudi Arabia and the rest of the Gulf Cooperation Council, who have comparatively less influence Iraq, will rely on Turkey to uphold Sunni interests.
The fall of Mosul will further divide Iraq's Kurds. The inevitable scramble for territory and influence will pit the Turkey-backed Kurdistan Democratic Party (KDP) against the Patriotic Union of Kurdistan, which is more closely aligned with Iran. Kirkuk, a city and province awash in oil, will be particularly contentious. The KDP will try to keep what it has gained there, while Baghdad, backed by Iran, will try to take it back. This will impede sustainable cooperation in energy production and revenue-sharing operations between Baghdad and Iraqi Kurdistan. So despite the considerable gains Kurds have made as a result of the fight against the Islamic State, ongoing competitions will stifle any efforts to build a unified Kurdish territory.
