The conclusion of an agreement between Turkey and the U.S.-led anti-ISIS coalition to open Turkish airbases for coalition aircraft conducting sorties against the Islamic State of Iraq and al-Sham (ISIS) marks a major shift in Turkish policy which will provide immediate boost to U.S. efforts to degrade and ultimately defeat ISIS. At the same time, Turkey began launching airstrikes and internal crackdowns targeting members of both ISIS and the outlawed Kurdistan Workers’ Party (PKK) in the wake of several days of violence which included an ISIS-linked SVEST attack inside Turkey and several PKK-linked assassinations of Turkish police officers. Turkey’s decision to escalate against both militant groups suggests that Turkey intends to leverage the coalition’s calls for further action against ISIS in order to assert its own strategic interest in limiting the expansion of armed Kurdish groups along the Turkish border. The government of Turkish President Recep Erdogan may also seek to utilize these security threats to increase its own political standing amidst ongoing negotiations to form a coalition government and a potential call for early elections. Over the near-term Turkey will face an expanded domestic threat from both ISIS and PKK militancy in the form of persistent violence against the Turkish state. Nonetheless, a sustained Turkish effort against ISIS’s networks in Turkey and northern Syria combined with the efforts of local anti-ISIS Syrian opposition forces has the potential to significantly disrupt the foreign fighter flows which provide ISIS with a key source of reinforcements, suicide bombers, and legitimacy as a global caliphate.