In December 2018, President Trump ordered the withdrawal of all U.S. troops from Syria. “We have won against ISIS. We’ve beaten them, and we’ve beaten them badly,” Trump announced, “Now it’s time for our troops to come back home.”1
The president’s decision amounted to a complete and sudden reversal of the policy his principal advisers had developed, which relied on the presence of roughly 2,000 U.S. troops and their local partners to crush the remnants of the Islamic State. The president’s advisers also sought to expel all Iranian-controlled forces from Syria while supporting UN-led negotiations to end the Syrian civil war. The U.S. military mission in Syria does not include offensive operations against the Iranian-controlled forces fighting on behalf of the Bashar al-Assad regime, but the presence of U.S. troops and their local partners generates substantial diplomatic leverage.
As a candidate in 2016, Trump made clear his aversion to continued involvement in Syria for any purpose other than defeating the Islamic State. “I don’t like Assad at all, but Assad is killing ISIS. Russia is killing ISIS. And Iran is killing ISIS,” he said.2 Surprisingly, Trump then chose in April 2017 to punish the Assad regime’s use of chemical weapons by launching 59 cruise missiles at military targets in Syria. A year later, he launched a second round of airstrikes after Assad used chemical weapons again.
In 2017, the U.S. focused on defeating the Islamic State, whose “capital” of Raqqa in northern Syria fell in October to the U.S.-backed Syrian Democratic Forces (SDF), in which Kurdish fighters play an outsized role. Trump sought to avoid further entanglement by reaching an agreement with Russian President Vladimir Putin for Russian troops to monitor a ceasefire that would prevent Assad’s forces as well as Iran and its proxies from approaching the Syrian border with Israel in the Golan Heights.
In early 2018, the administration began to address the long-term threat posed by Iran’s military presence in Syria. By maintaining troops in the northeast, the U.S. could prevent a resurgence of the Islamic State while keeping a resource-rich and strategically significant part of the country out of the hands of Assad and Iran. Then, in March, the president unexpectedly announced at a public rally that the U.S. would be leaving Syria “very soon.” “Let the other people take care of it now,” Trump said, “We are going to get back to our country, where we belong, where we want to be.”3 On the advice of his national security team, Trump quietly postponed consideration of a withdrawal.
In the summer of 2018, Russian forces, Assad’s troops and Iranian-backed militias violated the ceasefire Trump had negotiated with Putin, in the process deliberately bombing hospitals and civilian targets once again. Top administration officials made clear the U.S. would not hand Syria over to the Assad-Russia-Iran coalition. National Security Adviser John Bolton asserted in September, “We’re not going to leave [Syria] as long as Iranian troops are outside Iranian borders.”4
The president reportedly made the decision to withdraw from Syria during a phone call with Turkish President Recep Tayyip Erdogan. Trump’s principal advisers argued that the withdrawal would be a serious mistake, with Secretary of Defense James Mattis ultimately resigning shortly after the president publicly announced his decision. Moreover, Trump did not inform either congressional leaders or foreign allies before his announcement, nor did the Pentagon have time to plan how it would withdraw the troops or continue operations against the Islamic State without a presence in Syria. The timeline for the U.S. withdrawal from Syria remains uncertain for now, although the Pentagon announced the process has begun.
President Trump justified his decision to withdraw from Syria by erroneously and repeatedly asserting that the Islamic State had been defeated. Rather than recognizing the low cost and high impact of the mission in Syria, the president described it as a waste of soldiers’ lives and taxpayer dollars. Instead of acknowledging that America’s Kurdish and Arab partners fought a bloody ground war against the Islamic State, Trump suggested that only U.S. troops were engaged in fighting.
The process by which Trump arrived at his decision was also deeply flawed. He reversed a long-standing policy within a matter of days, leaving his own administration scrambling to contain the fallout.
The process by which Trump arrived at his decision was also deeply flawed. He reversed a long-standing policy within a matter of days, leaving his own administration scrambling to contain the fallout. The decision blindsided allied nations with troops in Syria as well as local partners who continue to suffer heavy casualties while fighting the Islamic State. Trump’s secretary of state, secretary of defense, and national security adviser all opposed the withdrawal. While a commander-in-chief has the right to overrule his advisers, Trump ignored the serious concerns they raised.
In addition to damaging the campaign against the Islamic State, the withdrawal from Syria undermines the president’s own strategy “to counter the [Iranian] regime’s destabilizing activity and support for terrorist proxies in the region.”5 The Assad regime plays a central role in what Iran calls its “axis of resistance.” For decades, Tehran has relied on Damascus as a conduit to pass funding and weapons to Hezbollah, enabling it to dominate Lebanon and prepare for a devastating war with Israel. In addition to protecting Assad, Iran is also building up its offensive capabilities in Syria so it can attack Israel directly.
At present, Iran relies mainly on air transport to bring men and materiel into Syria, but has begun to build a “land bridge,” or ground corridor, through which it could project power from western Iran to the Mediterranean. Effective U.S. control of northeast Syria blocks one potential route for the land bridge. The U.S. and its local partners also have a base further south at al-Tanf, along the Syrian-Iraqi border, which prevents Iran from establishing control of the main highway from Baghdad to Damascus. A withdrawal opens these routes to Iran and its allies.
A retreat from Syria would also provide substantial benefits to the Turkish president, an avowed Islamist with a record of human rights abuses. Erdogan has already disrupted the campaign against the Islamic State multiple times by launching military operations against the Syrian Kurds, and has threatened another offensive. Trump argues that the U.S. can trust Erdogan to prosecute the war against the Islamic State in Syria, yet it is doubtful whether the Turkish president has either the will or the ability.
The withdrawal from Syria also benefits Russia, which flagrantly violated the ceasefire to which Trump and Putin personally agreed last year. Russia has a strong interest in supporting Assad’s effort to reassert control over northeast Syria, where more than 90 percent of Syria’s oil is located, as well its most productive agricultural land. The more self-reliant Assad becomes, the less Russia must invest in supporting him. The same is true of Assad and Iran.
Trump has often criticized his predecessor for a reckless and premature withdrawal from Iraq in 2011 that contributed directly to the rise of the Islamic State. He is now on the precipice of repeating that error in Syria. Trump initially announced the immediate departure of all U.S. forces, but administration officials soon extended the timeline, until Trump himself said that there is no date certain for the U.S. departure. Nonetheless, Trump insists his original decision has not changed. What this means in practice remains uncertain.
President Trump was right when he said in 2017, “Conditions on the ground — not arbitrary timetables” should be the basis for any withdrawal. “America’s enemies must never know our plans or believe they can wait us out,” he added.6 Any withdrawal now should also be conditions-based.