On April 13, 2018, President Trump ordered the launch of air strikes against Syria in response to the Syrian government's apparent use of chemical weapons on civilians in the Syrian town of Douma a few days earlier.Footnote 1 The air strikes, which targeted several weapons-related facilities of the Syrian government,Footnote 2 were carried out in conjunction with the United Kingdom and France.Footnote 3
In announcing the strikes, Trump stated in a televised address:
One year ago, [Assad] launched a savage chemical weapons attack against his own innocent people. The United States responded with 58 missile strikes that destroyed 20 percent of the Syrian Air Force.
Last Saturday, the [Assad] regime again deployed chemical weapons to slaughter innocent civilians—this time, in the town of Douma, near the Syrian capital of Damascus. This massacre was a significant escalation in a pattern of chemical weapons use by that very terrible regime.
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The purpose of our actions tonight is to establish a strong deterrent against the production, spread, and use of chemical weapons. Establishing this deterrent is a vital national security interest of the United States. The combined American, British, and French response to these atrocities will integrate all instruments of our national power—military, economic, and diplomatic. We are prepared to sustain this response until the Syrian regime stops its use of prohibited chemical agents.
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In 2013, President Putin and his Government promised the world that they would guarantee the elimination of Syria's chemical weapons. [Assad's] recent attack—and today's response—are the direct result of Russia's failure to keep that promise. Russia must decide if it will continue down this dark path, or if it will join with civilized nations as a force for stability and peace. Hopefully, someday we'll get along with Russia, and maybe even Iran—but maybe not.
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America does not seek an indefinite presence in Syria under no circumstances. As other nations step up their contributions, we look forward to the day when we can bring our warriors home. …Footnote 4
In a press release issued the same day, the White House declared that while it had considered alternative explanations, it had assessed “with confidence” the Syrian government's responsibility for the chemical weapons attack on Douma.Footnote 5 Referencing photographs and video from “social media users, non-governmental organizations, and other open-source outlets” in Syria, it said that a “significant body of information” suggested that chlorine had been used in the attack, and that “additional information” indicated the use of the nerve agent sarin as well.Footnote 6 The White House also accused Syrian president Bashar al-Assad of carrying out collective punishment and executing the attack in a way calculated to inflict maximum suffering.Footnote 7
The Trump administration blamed Russia for shielding Syria from accountability, saying in a press release issued by State Department spokesperson Heather Nauert that “Russia … ultimately bears responsibility for these brutal attacks.”Footnote 8 Nauert also accused Russia of “breach[ing] its commitments to the United Nations as a framework guarantor … [and] betray[ing] the Chemical Weapons Convention and UN Security Council Resolution 2118.”Footnote 9 By contrast, Russian Foreign Minister Sergey Lavrov said in an interview that the chemical weapons attack was “staged” as part of a “Russophobic campaign” and “did not involve any chemical weapons.”Footnote 10
The United Kingdom and France, both of which participated in the air strikes, asserted that the air strikes complied with international law—the United Kingdom on a theory of “humanitarian intervention”Footnote 11 and France on less clearly specified grounds.Footnote 12 On the other hand, the United States has not offered a consistent or definitive international law justification for the air strikes.Footnote 13 Some states that did not participate in the strikes have expressed political support or “understanding” for the air strikes without discussing their legality, while others have taken stances that neither explicitly condemn nor condone the strikes.Footnote 14 Finally, some states, including Syria, Russia, China, and South Africa, have explicitly declared the air strikes to be illegal under international law.Footnote 15 For example, Russian president Vladimir Putin called the air strikes
[a]n act of aggression against a sovereign state that is on the frontline in the fight against terrorism [that] was committed without a mandate from the UN Security Council and in violation of the UN Charter and norms and principles of international law.Footnote 16
Russia also introduced a Security Council resolution condemning the air strikes, which was supported by China and Bolivia.Footnote 17 Eight Security Council members, including the United States, United Kingdom, and France, opposed the resolution, while four countries abstained.Footnote 18
Shortly after the strikes, Trump sent a letter to Congress regarding his decision to launch air strikes against Syria and his domestic legal justification for doing so. It reads:
At approximately 9:00 p.m. Eastern Daylight Time on April 13, 2018, at my direction, United States military forces, acting in concert with French and British military forces, struck Syrian military chemical weapons-related facilities. The targets of the combined operation were a scientific research center installation, a storage facility, and a bunker. I directed this action in response to the Syrian government's continued and unlawful use of chemical weapons, including in the horrific attack in Duma, Syria, on April 7 that injured or killed numerous innocent civilians. The purpose of this military action was to degrade the Syrian military's ability to conduct further chemical weapons attacks and to dissuade the Syrian government from using or proliferating chemical weapons.
I acted pursuant to my constitutional authority to conduct foreign relations and as Commander in Chief and Chief Executive and in the vital national security and foreign policy interests of the United States to promote the stability of the region, to deter the use and proliferation of chemical weapons, and to avert a worsening of the region's current humanitarian catastrophe. The United States will take additional action, as necessary and appropriate, to further its important national interests.
I am providing this report as part of my efforts to keep the Congress fully informed, consistent with the War Powers Resolution (Public Law 93-148). I appreciate the support of the Congress in this action.Footnote 19
Trump had sent a similar report to Congress in April 2017 after ordering a prior round of air strikes against a Syrian government airfield in response to the apparent use of chemical weapons by Syria.Footnote 20
On May 31, 2018, the Office of Legal Counsel at the Department of Justice issued a twenty-two page opinion defending the legality of the strikes as a matter of domestic law, although not discussing the legality of the strikes under international law.Footnote 21 Relying on “the legal opinions of executive advisers and the still weightier precedents of history,” the memorandum determined that “the President, as Commander in Chief and Chief Executive, has the constitutional authority to deploy the military to protect American persons and interests without seeking prior authorization from Congress.”Footnote 22 The memorandum identified four interests that the Office of Legal Counsel had previously recognized as appropriate justifications: “the protection of U.S. persons and property”; “assistance to allies”; “support for the United Nations”; and “promoting regional stability.”Footnote 23 The memorandum continued:
In recent years, we have also identified the U.S. interest in mitigating humanitarian disasters. … With respect to Syria, in April 2017, the President identified the U.S. interest in preventing the use and proliferation of chemical weapons … .
The President identified three interests in support of the April 2018 Syria strikes: the promotion of regional stability, the prevention of a worsening of the region's humanitarian catastrophe, and the deterrence of the use and proliferation of chemical weapons. Prior to the attack, we advised that the President could reasonably rely on these national interests to authorize air strikes against particular facilities associated with Syria's chemical-weapons program without congressional authorization.Footnote 24
The opinion also addressed “whether the President could expect the Syria operations to rise to the level of a war requiring congressional authorization.”Footnote 25 After reviewing prior precedents, it concluded that “[T]he proposed Syrian operation, in its nature, scope, and duration, fell far short of the kinds of engagements approved by prior Presidents under Article II.”Footnote 26 In reaching this conclusion, the opinion noted the absence of ground troops, the narrow focus of the mission, and its short duration. It added:
Standing on its own, the attack on three Syrian chemical-weapons facilities was not the kind of “prolonged and substantial military engagement” that would amount to war. … We did not, however, measure the engagement based solely upon the contours of the first strike. Rather, in evaluating the expected scope of hostilities, we also considered the risk that an initial strike could escalate into a broader conflict against Syria or its allies, such as Russia or Iran. …
We were advised that escalation was unlikely (and reviewed materials supporting that judgment), and we took note of several measures that had been taken to reduce the risk of escalation by Syria or Russia. … Given the absence of ground troops, the limited mission and time frame, and the efforts to avoid escalation, the anticipated nature, scope, and duration of these air strikes did not rise to the level of a ‘war’ for constitutional purposes.Footnote 27
The April 2018 air strikes came at a time when the Trump administration was considering scaling back its military presence in Syria. More specifically, Trump has signaled his interest in withdrawing U.S. troops after all of the territory held by ISIS has been reclaimed and has called upon the United States’ regional Arab allies to assume responsibility for post-war stabilization and reconstruction efforts.Footnote 28 If such an approach comes to be implemented, it would also reduce the U.S. role in supporting non-ISIS rebel groups engaged in an ongoing conflict with the Russian-backed Syrian government.Footnote 29
In the meantime, both Congress and the judicial branch are considering issues related to the domestic legal authority of the executive branch's campaign against ISIS. Members of Congress have introduced various bills to explicitly authorize the use of military force against ISIS and other specified terrorist groups, while simultaneously winding down or eliminating earlier authorizations from 2001 and 2002 that were aimed at responding, respectively, to the September 11, 2001 attack and the threat posed by the Saddam Hussein regime in Iraq.Footnote 30 In the judicial branch, at least two ongoing cases challenge the executive branch's current domestic legal authority for its military campaign against ISIS. One of these cases, Smith v. Trump (formerly Smith v. Obama) was brought by an Army captain; he lost on jurisdictional grounds in the federal district court and his case is presently on appeal in the D.C. Circuit.Footnote 31 In the other case, Doe v. Mattis, an American citizen who was captured in Syria, allegedly while fighting for ISIS, is challenging the legality of his detention, which in turn may depend upon the legality of the conflict against ISIS as a matter of U.S. domestic law.Footnote 32 He is also challenging an attempt by the United States government to transfer him to a third country.Footnote 33
