 Turkey has just announced a military incursion into northern Syria. Turkish President Erdogan is saying this is to clear what he calls a terrorist corridor. The Kurds are raising alarms about a humanitarian catastrophe. This is the latest. I'm Mona Yagubian. What led to the U.S. decision to withdraw from military posts on the Syria-Turkish border? The decision came after a late-night phone call between President Trump and Turkish President Erdogan. There had been a long-standing attempt to secure some kind of security mechanism along Syria's northern border that would satisfy Turkey's security concerns but also protect Kurdish interests and allow the U.S. to continue its partnership. It seems pretty clear that those talks have broken down and that precipitated the decision to pull back the U.S. special forces from the border. What are the major risks associated with Turkey's incursion? Turkey's incursion creates a real dire situation inside Syria. First, there's the potential for a new conflict between Turkey and the Kurds. The incursion also risks the long-standing counter-ISIS mission. We rely on our Kurdish partners to guard ISIS detention facilities. They may now be pulled up to fight the Turks in the north and that risks prison breaks and other instability in those areas. There are also significant humanitarian concerns that come along with any conflict. Hundreds of thousands of people could be displaced from their homes. This is in an area that has been relatively stable up until now. What does this mean for U.S. policy in Syria moving forward? Well, we're at a moment of great uncertainty at this point. The most important question really will be the fate of the U.S. presence in Syria. Without knowing how far and how deep the Turkish incursion will go, we could face the situation in which the U.S. is forced to withdraw completely. If the U.S. is forced to withdraw from Syria, it will send a negative signal to our allies about the U.S.'s reliability as a partner. A U.S. withdrawal would also open up a vacuum that could be filled by adversaries such as Russia, Iran, or the Syrian regime.