Dr. Christopher Bolan has served in Jordan, Tunisia, and Egypt and worked as a Middle East foreign policy advisor to Vice Presidents Gore and Cheney.  He presently teaches and researches national security issues at the Strategic Studies Institute at the U.S. Army War College.  He can be found on Twitter @DrChrisBolan.  Divergent Options’ content does not contain information of an official nature nor does the content represent the official position of any government, any organization, or any group.  

National Security Situation:  U.S. Force Posture in Syria following the strategic defeat of the Islamic State (IS).

Date Originally Written:  February 23, 2018.

Date Originally Published:  February 26, 2018.

Author and / or Article Point of View:  Author writes from the perspective of a seasoned regional analyst focusing on the Middle East.

Background:  The U.S. military battle against IS is nearing completion in both Iraq and Syria.  An intensified U.S. air campaign in support of local ground forces has effectively (and literally) destroyed the physical infrastructure of the so-called IS “caliphate” that at its peak occupied a territorial expanse roughly equivalent to that of Great Britain, extended its brutal authority over 11 million people, and gave it access to annual economic resources estimated at $1 billion[1].  In Iraq, a combination of U.S.-equipped and trained Iraqi security forces fighting alongside a variety of Shi’ia militia groups (some backed by Iran) allowed Iraqi Prime Minister Haider al-Abadi to declare victory over IS in early December 2017.  In Syria, Kurdish and Syrian Arab forces enabled by U.S. special operations forces and an aggressive coalition bombing campaign liberated the IS caliphate’s self-proclaimed capital at Raqqa last fall and IS is now largely restricted to the Idlib province.

Significance:  The combined coalition military advances in both Iraq and Syria represent the strategic defeat of IS as a terrorist organization capable of holding territory in the Middle East.  These visible defeats strike at the heart of IS’s claim to leadership of the global jihadist movement.  The destruction of the ‘caliphate’ leaves IS a much diminished and impoverished organization.  Nonetheless, these significant battlefield victories do not entirely eliminate the IS threat as it remains capable of inspiring (if not planning) attacks that threaten regional instability and target Western interests.  In Iraq, a continued U.S. military presence codified through traditional security assistance programs in coordination with the central Iraqi government in Baghdad is virtually a foregone conclusion.  However, Syria presents a different strategic calculus for U.S. policymakers as they weigh options at a time when Syrian President Bashar al-Assad appears to be consolidating his control with the active support of his allies in Moscow and Tehran.

Option #1:  Establish a long-term U.S. military presence in Syria.  U.S. Secretary of State Rex Tillerson announced in mid-January 2018 that the U.S. “will maintain a military presence in Syria” for an indefinite period of time[2].  In doing so, Tillerson committed the U.S. to achieving an expansive set of strategic objectives that include: ensuring the defeat of IS and al-Qa’ida; diminishing the influence of Iran; facilitating the return of Syrian refugees; advancing a United Nations (UN)-led political resolution to the crisis; and guaranteeing that Syria is free of weapons of mass destruction.

Risk:  The continued presence of the U.S. military in Syria is opposed to one extent or another by virtually every other important actor in Syria including the internationally recognized government of President Bashar al-Assad, Russia, Iran, and even North Atlantic Treaty Organization (NATO) ally Turkey.  The proximate defeat of IS and the failure of the U.S. Congress to explicitly authorize U.S. military operations in Syria seriously erodes the international and domestic legal basis for this presence.  More importantly, the actual risk of direct military conflict between the U.S. and any one of these outside actors or their local proxies is real and growing.  In early February 2018, the U.S. conducted defensive strikes killing hundreds of Syrian troops and dozens of Russian contractors.  Meanwhile, the U.S. announcement that it was creating a Kurdish security border force in northern Syria prompted the ongoing Turkish incursion into Afrin that is now threatening a direct military confrontation between a NATO ally and both the Syrian Army and U.S-backed Kurdish militias.  Lastly, Turkish President Recep Erdogan has directly threatened the U.S. with a punitive ‘Ottoman slap’ if the U.S. doesn’t end its support for Kurdish elements or abandon its positions further east in Manbij[3].

Gain:  Russian and Iranian military support to Assad have given him the decisive advantage in the civil war restoring his control over the majority of Syria’s population and key economic centers.  Given this existing reality, an indefinite U.S. military presence in eastern Syria may well be the only concrete leverage that the U.S. has to influence the behavior of the other actors in this crisis.  To accomplish the wide-ranging goals of U.S. strategy as articulated by Tillerson, however, this presence will likely need to maintained or even expanded for the foreseeable future.

Option #2:  Withdraw U.S. military forces from Syria.  The U.S. could use the recent battlefield victories against IS as a justification to declare ‘mission accomplished’ and begin a phased and conditions-based withdrawal of forces from Syria.

Risk:  As Tillerson himself argued, a U.S. withdrawal from Syria could create a security vacuum which IS and other Islamist terrorist groups would exploit to regain a foothold in eastern Syria.  Moreover, with the UN Geneva peace process moribund, the absence of a physical U.S. presence on the ground will leave policymakers with precious little direct leverage to influence the ultimate political or military outcomes in Syria.  This approach also feeds the perception of declining U.S. regional influence and could bolster the reputation of Russia and Iran as reliable partners.

Gain:  U.S. policymakers could use a phased withdrawal as diplomatic leverage to press for the withdrawal of all foreign forces from Syria to include Russia, Iran, and their paramilitary proxies (e.g., Hizbollah, Islamic Revolutionary Guards Corps).  The scale and timing of the U.S. withdrawal could be explicitly tied to the departure of these other foreign forces, as well as to progress in defeating the remnants of IS.  This would accomplish the two most critical U.S. strategic objectives outlined by Tillerson:  the defeat of IS; and reducing the influence of Iran.  Additionally, such a phased withdrawal would relieve the U.S. of the substantial costs of reconstruction in Syria which is estimated to easily exceed $250 billion[4].  Finally, the prospect of an imminent U.S. military withdrawal would increase pressure on Kurdish elements to come to a workable compromise with both Damascus and Ankara and thereby bolster prospects for a durable political outcome in Syria that enhances regional stability.

Other Comments:  None.

Recommendation:  None.


[1] John Feffer, “The Fall of the House of ISIS,” Foreign Policy in Focus, October 25, 2017.  Available at: http://fpif.org/fall-house-isis/.

[2] Secretary of State Rex W. Tillerson, “Remarks on the Way Forward for the United States Regarding Syria,” Hoover Institute at Stanford University, January 17, 2018.

[3] Bethan McKernan, “Turkish President Erdogan offers US ‘Ottoman Slap’ ahead of Rex Tillerson’s visit to Turkey,” The Independent, February 15, 2018.

[4] UN estimate quoted by Somini Sengupta, “Help Assad or Leave Cities in Ruins?  The Politics of Rebuilding Syria,” The New York Times, December 3, 2017.