Those troops are not there on a combat mission but only in an advisory role to prevent the return of ISIS and also to provide some US leverage over events in Syria, whose regime is supported by Russia and Iran.
An American pull-out also allows the Turks free rein to carry out military operations against America’s allies in the largely Kurdish Syrian Democratic Forces (SDF), which were the ground troops that retook Syria from ISIS. The SDF is regarded as a terrorist group by Turkey, which has a restive Kurdish minority.
If there is one key lesson learned from fighting jihadist terrorist groups in the 18 years since 9/11, it is that they thrive in weak or failing Muslim states such as Syria, and other countries where the United States has little to no presence.
What is particularly odd about Trump’s policy shift on Syria is that it does exactly what Trump repeatedly warned against during his presidential campaign: it gives America’s enemies an early heads-up about US military plans.
During his campaign, Trump also had correctly critiqued the total American troop withdrawal from Iraq under Barack Obama in 2011 as helping pave the way for the rise of ISIS.
What Trump’s announcement on Syria also underlines is the collapse of any kind of deliberative national security process. Trump appears to make unilateral decisions surrounded by a cabinet of yes-men and acolytes because he has chased out advisers like Mattis, former National Security Adviser H.R. McMaster, former Secretary of State Rex Tillerson, and former Chief of Staff John Kelly, all of whom tended to push back against Trump’s more ill-advised decisions.
Such as a precipitous withdrawal from Syria.