Following the recent safe return of 46 Turkish hostages held by the Islamic State, hopes were raised in the United States that Turkey would finally commit to joining the U.S.-led coalition now fighting the group. But Turkey's willingness to contribute to the coalition remains constrained by the legacy of its ill-fated Syria policy, as well as by a fundamental strategic disconnect between President Recep Tayyip Erdogan's government and U.S. President Barack Obama's administration.

Since Syria's civil war began three years ago, Turkey has provided logistical and financial support to virtually all elements of the Syrian opposition, while allowing them to use Turkish territory to regroup after launching military operations across the border.

Committed to regime change in Syria, Turkey turned a blind eye to some of these groups' brutal tactics, radical ideologies and big ambitions. The fear now is that this benign neglect has allowed the Islamic State to embed itself in Turkey and build the capacity to conduct terrorist activities on Turkish soil — and thus to retaliate for Turkish participation in the U.S.-led coalition.