By David L Philips/President Donald J. Trump said he will “absolutely do safe zones in Syria.” Establishing safe zones is a consequential decision. Benefits and risks must be carefully considered.The devil is in the details. Where will safe zones be established? How will safe zones be enforced? Which local fighters can the US rely on?

Safe zones are viable in Syria’s south, along its border with Jordan, and in the north on Syria’s border with Turkey.

The Southern Front, a coalition of CIA-vetted Syrian rebel groups, controls the desert region adjoining Jordan. The Southern Front is supported by Jordan, Saudi Arabia, the United Arab Emirates, and Israel. It represents a bulwark against Iranian influence and Iranian backed armed groups such as the Islamic Revolutionary Guard Corps and Hezbollah.

Syrian Democratic Forces (SDF), would secure the northern safe zone. The SDF includes 40,000 Kurdish fighters comprising Peoples Protection Units (YPG). The provinces of Jazeera, Kobani and Afrin encompass the northern zone. There is precedent for cooperation with the SDF. The US is supporting SDF fighters in the battle to retake Raqqa, the ISIS capital.

Safe zones will require the US to expand its deployment of Special Forces. The US would also have to provide a more sophisticated arsenal to the Southern Front and SDF.

In addition, safe zones will require air power. De-conflicting with Russian warplanes will be critical.

Safe zones could yield substantial benefits.

Safe zones will shrink the territory controlled by ISIS. They will be a launch point for rebel groups fighting ISIS. Safe zones will also help mitigate the humanitarian crisis, serving as a sanctuary for displaced Syrians.

There are also costs.

Establishing safe zones will require significant military assets. US troops will be in harm’s way. Enforcing safe zones also risks putting the US on a slippery slope to further involvement in Syria’s civil war.

The northern safe zone risks a further falling out with Turkey, which has staked out its own zone of influence in Jarablus. Turkey adamantly opposes US cooperation with the YPG, which it sees as an extension of the Kurdistan Workers’ Party (PKK). A safe zone along Turkey’s border will be viewed as a nascent Kurdish state, protected by the US the same way that the US protected the Kurdistan Region of Iraq.

In response, Turkey could deny US access to Incirlik air force base. Then Pentagon planners would be compelled to ramp up operations from Jordan, Cyprus, and Iraqi Kurdistan.

Tense US-Turkish relations are exacerbated by Trump’s rhetoric about radical Islamic terror, listing the Muslim Brotherhood as a foreign terrorist organization, and restrictions on immigration of Muslims. Not only was Turkey the primary supporter of ISIS, it has become increasingly Islamist and anti-Western.

Military action will not occur in a vacuum. Safe zones will go hand in hand with US diplomatic engagement.

Russia and Turkey have sought to exclude the US from talks aimed at ending Syria’s civil war. The rancorous collapse of last week’s “peace conference” in Astana, backed by Russia and Turkey, showed the limits to Russian-Turkish diplomacy and the indispensable role of the US in mediating and enforcing a peace agreement.

Trump must carefully consider both the benefits and risks of safe zones. Safe zones will require a sustained military and diplomatic commitment. Shooting from the hip is no way to go to war.

David L. Phillips is Director of the Program on Peace-building and Rights at Columbia University’s Institute for the Study of Human Rights. He served as a senior adviser and foreign affairs expert to the US State Department during the administrations of Presidents Clinton, Bush, and Obama.(Huffington Post)