First, the interlinked civil wars in Syria and Iraq are the product of a regional geopolitical struggle in which Turkey and Iran are key players who exploit the ethnic and sectarian fault lines of their neighbors. Despite improved cooperation between Iran and Turkey on bilateral issues — including the role of Kurds in Syria — they compete for influence in Iraq and Syria. From Ankara’s perspective, the disagreement with Baghdad on Turkey’s presence in Bashiqa is not so much between Turkey and Iraq as it is between Turkey and the Shiite-dominated Iran-leaning government in Baghdad. Further, Ankara maintains that the Iraqi government’s legitimacy is eroded by years of civil war and sectarian policies that persecuted Iraq’s Sunnis and Sunni Turkomen and alienated its Kurds.

Second, Ankara is concerned not just about Mosul proper but also about the surrounding area, where Iran would like to establish an outpost at the junction of the Iraqi, Syrian, and Turkish Kurdish regions. Control of this territory would allow Iran to project power—directly or via proxies—on behalf of the Assad regime in Syria. It would also give Iran the ability to harass the Kurdish Regional Government in Iraq. The Turks believe Iran is seeking a land corridor to the Mediterranean shores of Syria and Lebanon for which Mosul would present the shortest route from Iran – an outcome they want to block.

Third, Turkey has historic and cultural ties with Mosul and its Sunni Arab and Sunni Turkomen populations. There is even a sense among Turkish leaders, as expressed by President Erdogan’s chief adviser Ilnur Cevik, that this region, along with northern Syria, should have never been relinquished after the First World War. Key Arab leaders in Mosul have a similar appreciation for shared history and view strong ties with Turkey as a critical element of balance in dealing with the threat of Shiite militias and Iran. Turkey believes that the Sunni Turkoman population of the area is particularly vulnerable and has voiced concerns about possible plans by Iran and sectarian militias to force demographic changes by displacing Sunni Turkoman populations from areas around Mosul such as Tel Afar.