On December 19, 2018, President Trump gave the order to withdraw all U.S. forces from Syria. This withdrawal is a significant tactical blow to U.S. allies in the country, but at the same time, Trump made the correct legal decision. While the foreign-policy ramifications of leaving local allies in the lurch will stain America’s reputation, the Trump administration is constrained by the domestic foreign affairs legal framework. Under foreign-affairs law, Trump made the appropriate decision, but it will nonetheless be a painful one.

The Situation in Syria

U.S. forces entered Syria back in September 2014. The purpose of this mission was clear: stop the burgeoning pseudo-terrorist country created by the Islamic State, also known as ISIS. The Islamic State had grown into a territorial state following the start of the Syrian Civil War, which fractured that country. At its height in 2015, the Islamic State, from its capital at Raqqa, controlled nearly half of Syria and a significant part of northern Iraq, including the regional capital of Mosul.

Since mid-2015, the Islamic State was gradually pushed back, losing all of its major cities in 2017. While a few pockets of resistance fighters remain, and a shadow state exists online which still commands terrorist attacks around the world, the Islamic State as a territorial country is all but dead. Iranian President Hassan Rouhani and Russian president Vladimir Putin both declared victory over the Islamic State in November 2017.

But while the Islamic State may be removed as a factor from the Syrian Civil War, the war is very much alive. The Syrian government of Bashar al Assad holds the most land, controlling practically all of southern Syria, including the capital of Damascus. The extremely divided anti-government forces are for the most part in sharp decline, only holding pockets of territory concentrated in northwestern Syria. The final combatant, the Kurdish-dominated Syrian Democratic Forces (SDF), controls most of northern Syria.

Beyond the map in Syria, each of the three forces has major foreign governments backing them. The Assad regime has support from Russia, Iran, and Hezbollah in Lebanon. The anti-government forces have been strongly supported by Turkey, and to a lesser extent by countries in the Arabian Peninsula. The SDF is mostly supported by the United States.

The SDF mostly expanded its holdings against the Islamic State, which was in line with U.S. goals. While the SDF posed a potent military threat in the Syrian Civil War, its position has become increasingly complicated in the last year with the introduction of Turkish troops into the Syrian conflict. Turkish forces, at least nominally supporting the anti-government forces, took the major city of Afrin from the SDF in March 2018 and have advanced on the de facto capital of the SDF, Manbij. Turkey has a significant minority population of Kurds itself and has vigorously shut down any attempt at autonomy for the Kurds. This animus is at least partially driving the significant Turkish involvement in Syria. It also severely complicated U.S. involvement in Syria for the last year since Turkey is, despite some recent bad blood, a U.S. ally, as is the SDF.

The effective status quo in Syria is that as Turkish-led anti-government forces focus on the SDF, the two forces continued to weaken each other while allowing the Assad government to further strengthen its position. The U.S. withdrawal effectively removes any serious foreign-backing from the SDF, leaving them to fight to survive against anti-government and Assad forces. This is hardly the first time America has left its Kurdish allies in the region in the lurch, and this move will further diminish U.S. standing in the region. It will also effectively shut out America from the negotiating table, at which Russia, Iran, and Turkey will no doubt have a seat when the Syrian Civil War is finally at an end. On the other hand, a tactical withdrawal at this point does prevent the possibility of a larger conflict breaking out with Russia, Iran, or Turkey over Syria.

Lack of Legal Authorization to Stay

In addition to the agonizing foreign-policy considerations, the Trump administration no doubt looked at its own domestic authorization to remain in Syria. Under the War Powers Resolution, the president’s power to enter into hostilities is extremely limited and involves a number of Congressional reporting requirements as well as time limits on how long U.S. forces can remain committed abroad.

One exception to the War Powers Resolution is if Congress has provided authorization to act. The 2001 Authorization for Use of Military Force (AUMF) allowed the United States to fight anyone who was a part of or substantially supported the groups that carried out the 9/11 terrorist attacks, namely Al Qaeda and the Taliban. As an offshoot of Al Qaeda, the Islamic State fell under the scope of the AUMF. But now, with the declared victory over the Islamic State, this justification is gone.

The Obama administration Office of Legal Counsel (OLC) developed a legal framework in 2011 for engaging in foreign-military operations without Congressional approval if it was for a “national interest” and the operation did not constitute “war,” meaning an operation that was limited in nature, scope, and duration. Supporting allies was upheld as a national interest in a 2014 OLC opinion, so remaining to support the SDF could work. It could also be argued that America has carried out targeted strikes against the Assad regime since 2017, so it has already been fighting another enemy. However, any further military support for the SDF risks a wider war in the region, potentially with the serious military powerhouses of Russia, Iran, and Turkey. Therefore, meeting the second element of this test would be tenable at best.

Even if the Trump administration felt that they could justify further operations in Syria under the 2011 OLC framework, it would still be subject to the War Powers Resolution limitations, including a sixty-day limit on the campaign. The Obama administration legal advisor for the State Department, Harold Koh, developed a framework that held that if an operation is limited and has a low risk of exposure to armed forces and escalation, it does not qualify as “hostilities,” and is therefore not subject to the War Powers Resolution restrictions. It would be hard enough to argue that remaining in Syria would not rise to the level of war, however, let alone the lower level of mere hostilities.

Legally Correct

Without Congressional approval, the Trump administration could not use the 2011 OLC or the Koh frameworks to authorize U.S. forces to remain in Syria. Although U.S. foreign-affairs law is admittedly murky, this leaves the Trump administration without legal authorization to maintain an operation in Syria. This withdrawal will create serious negative consequences for the SDF, the U.S. reputation in foreign relations, and the balance of power in Syria and the wider Middle East. Although the withdrawal was a tactically questionable choice, the Trump administration did ultimately make the best legal choice.

Michael Goodyear is a J.D. Candidate at University of Michigan Law School and holds an A.B. from the University of Chicago.

Image: Reuters