President Donald Trump took the world by surprise when he announced last December that American forces would withdraw from Syria. In a Twitter video posted on December 19, Trump declared, “Our boys, our young women, our men – they’re all coming back, and they’re coming back now.”

The Syrian Civil War began with civil uprisings against President Bashar al-Assad in 2011, as part of the Arab Spring. Since then, the United States has backed the rebels of the Free Syrian Army by providing funding and supplies. In addition, American ground forces have helped train and equip Kurdish rebels. The United States has also led a coalition in executing air strikes to combat ISIS, which exerts significant influence in the area.

As of December, ISIS controls two small regions near the southeastern border of Syria, while American-backed rebels control the north. The remainder of the country is controlled by the Russian-backed Syrian government.

Since his campaign, President Trump has expressed interest in ending American involvement in open-ended military commitments. In a tweet on December 19, Trump said, “We have defeated ISIS in Syria, my only reason for being there during the Trump Presidency.” President Trump initially ordered the military to withdraw within 30 days, but has extended the time frame to four months.

Following the announcement, Defense Secretary Jim Mattis resigned, citing  disagreements with the president on foreign policy as the primary reason for his departure. In his resignation letter, Secretary Mattis addressed the President, saying, “My views on treating allies with respect and also being clear-eyed about both malign actors and strategic competitors are strongly held. Because you have the right to have a Secretary of Defense whose views are better aligned with yours on these and other subjects, I believe it is right for me to step down from my position.”

The Pentagon and other high-ranking government officials also immediately opposed the President’s decision. Secretary Mattis argued that withdrawing from Syria would surrender control of the region to Russian and Iranian influence. Gen. Joseph Votel, the commander of United States Central Command, argued that withdrawing would abandon Kurdish fighters who were instrumental in fighting ISIS and leave them vulnerable to Turkey, who classifies them as terrorists. In a joint statement with two Democrat senators, Sen. Lindsey Graham (R-SC) said, “I don’t know how this decision was made; it literally came out of left field. It has rattled the world. None of us believe that ISIS has been defeated.”

However, President Trump’s decision received support from Robert S. Ford, who served as ambassador to Syria under the Obama administration. Mr. Ford said, “The whole Syrian conflict is about Syrians’ relations with other Syrians. Two thousand special operators and a dozen or two American diplomats can’t fix that.”

On Sunday, January 6, Mr. Trump’s National Security Advisor John R. Bolton added conditions to the withdrawal which were absent from President Trump’s original announcement. According to Mr. Bolton, American troops would remain in Syria until ISIS is completely defeated and Turkey promises not to attack Kurdish fighters allied with the United States. However, months or even years might pass before these conditions are fulfilled.

Mr. Trump also appeared to turn away from previous statements that an immediate withdrawal would be possible. In a tweet last Monday, Mr. Trump said, “No different from my original statements, we will be leaving at a proper pace while at the same time continuing to fight ISIS and doing all else that is prudent and necessary!” Despite the updates, the American military began withdrawing equipment from the region last Friday.