The International Crisis Group reports:

Trump’s decision to pull military forces out of Syria is the latest wild swing in U.S. Syria policy during his presidency, as the U.S. national security staff has repeatedly battled the president’s own instinct to avoid open-ended engagements in the Middle East. Until Trump’s about-face, those officials tied the presence of U.S. troops to ISIS’s “enduring defeat”, which, per their expansive definition, required fundamental change to Syria’s political system and the exit of Iranian-commanded forces from Syria. Now Trump has reasserted himself. “We have defeated ISIS in Syria, my only reason for being there during the Trump Presidency”, he tweeted on the morning of the 19 December withdrawal announcement.

President Trump first made the policy shift – unbeknownst to the State Department or the Pentagon – during a 15 December telephone call with Turkish President Erdoğan. Over the previous month, Turkey had stepped up its pressure on Washington over the U.S. presence in north-eastern Syria. It had become clear to Ankara that ISIS’s “enduring defeat” meant Washington’s continued sponsorship of the SDF and support of an SDF-controlled territorial entity. The SDF is led by the People’s Protection Units (YPG), the Syrian manifestation of the Kurdistan Workers’ Party (PKK), which has waged a decades-long insurgency in Turkey; Ankara accordingly considers it a terrorist organisation and any U.S. support for it intolerable. When the U.S. military established observation posts along the Syrian-Turkish border in late November – to protect Turkey from cross-border infiltration, U.S. officials claimed – Ankara only grew angrier, viewing the move as a hostile act designed to shield its mortal enemy, the PKK.

On 12 December, Erdoğan announced that Turkish forces would intervene in Syria “within days”. This declaration set off alarm bells in Washington. The Pentagon warned that an attack on Syria’s north east would be “unacceptable”. When Trump spoke to Erdoğan on 15 December, U.S. officials expected him to forcefully reiterate that message. He did not. Instead, he shocked his own staff by telling the Turkish president that an attack by Turkey made no sense since the U.S. would be imminently withdrawing from Syria. Summarising the mood among some, a top official, referring to the chaotic U.S. withdrawal from Vietnam decades ago, reportedly commented, “I was not hired to preside over another Saigon”.

Stunning as it was, Trump’s decision should not have come as a real surprise. He has consistently emphasised that his interest in Syria is limited to defeating ISIS. In March 2018, he undercut a previous open-ended commitment to remaining in Syria by declaring, unprompted, that the U.S. would withdraw its forces from Syria “very soon”. In subsequent internal deliberations, he opted to pull out of Syria even at the potential cost of leaving a vacuum that, his aides warned, could be filled by Russia and Iran.

In the ensuing months, Trump’s national security staff – with an assist from French President Emmanuel Macron – convinced him to remain in Syria as part of a regionwide strategy of “maximum pressure” on Iran. But that consideration could only override his hard-wired preferences for so long.

In truth, from the outset the Trump administration’s plan to use the U.S. presence in Syria’s north east to curtail Iranian influence in Syria was both unrealistic (a few thousand U.S. troops were never going to make a discernible difference to Iran’s influence) and impracticable. It also risked inviting a dangerous counter-escalation by the Syrian regime and its allies. The withdrawal announcement arguably solves those potential problems.

But if it might address some problems, it could create another: for all their talk of ISIS’s “enduring defeat”, U.S. officials may have given it a new lease on life. Indeed, if a rushed withdrawal prompts a military free-for-all involving the SDF, Syrian regime and Turkish forces, ISIS could exploit the ensuing chaos to stage a comeback. More broadly, and ironically, by stretching the concept of ISIS’s “enduring defeat” to include an assortment of dubiously related goals over an unlimited timeframe – rather than setting a discrete goal and planning for a managed exit – U.S. officials may have missed the opportunity to secure the counter-ISIS campaign’s gains after a U.S. withdrawal. Instead, they may have set up the U.S. for a sudden, wrenching exit that raises the risk that ISIS’s defeat could be at least partially undone.

Trump’s tweet notwithstanding, ISIS is not yet defeated. It retains a stubborn territorial foothold along the banks of the Euphrates near the border with Iraq, where its fighters have held off the SDF for more than a year. It has underground cells that continue to carry out bombings and assassinations beyond that river enclave in both Syria and Iraq. It also has an unknown number of sympathisers among local communities that the organisation ruled for three years.

Effectively defeating ISIS does not require a long-term U.S. military presence in north-eastern Syria. An ongoing U.S. military deployment could in fact stoke destabilising resentments over the medium term, as the Syrian regime and others encourage loyalists and disgruntled locals to engage in violence and sabotage. Eventually, U.S. forces were going to – indeed should – leave. But this ought to have been preceded by a minimum of preparation. Instead, promises of a sustained presence were followed by the announcement of a swift exit. An abrupt, uncoordinated U.S. withdrawal could expose the U.S.’s Kurdish allies to deadly attack by Syrian regime and Turkish forces, with the ensuing chaos allowing ISIS to make a resurgence. [Continue reading…]