President Trump’s first 100 days have been marked by a flurry of U.S. military activity. The Trump administration, for example, ordered a botched special forces raid against Al-Qaeda in Yemen that resulted in the deaths of at least twenty-five civilians; launched a cruise-missile attack on a Syrian air field following the Syrian government’s reported use of chemical weapons; dropped the largest nonnuclear bomb in U.S. history on ISIS targets in Afghanistan; classified Somalia as an “area of active hostilities,” thus loosening restrictions on lethal targeting; and escalated tensions with North Korea over its nuclear arsenal. Draft executive orders leaked to the press also revealed the administration’s plan to bring ISIS detainees to Guantanamo and lift the ban on CIA black-site prisons (subsequent drafts dropped the latter provision).
While it is impossible to anticipate the future course of military actions under the Trump administration, such actions will likely be frequent, unpredictable, and destabilizing. Trump’s use of military force has already raised significant legal concerns. The U.S. cruise-missile strike in Syria highlights several of them.
The strike in Syria contravenes both international and domestic limitations on the use of force. Article 2(4) of the UN Charter prohibits signatory states from using force against the territorial integrity of another state without its consent, and neither of the two exceptions to this prohibition applies. The UN Security Council did not authorize the strike, and the strike was not undertaken in self-defense within the meaning of Article 51 of the UN Charter. Indeed, the United States makes no claim of self-defense, asserting that the strike “was intended to deter the [Syrian] regime from using chemical weapons again.” By contrast, the U.S. has asserted collective self-defense as the justification for strikes against ISIS in Syria, based on Iraq’s request for assistance against the terrorist organization.
Some scholars argue that there is an emerging customary international norm of humanitarian intervention that provides an alternative ground for using force on the territory of another state to prevent atrocities. But, the status of this norm is highly contested, and the U.S. strike against Syria provides a poor case for it. The Trump administration not only failed to garner international support for the strike, but other policies, such as the ban on the admission of Syrian refugees, also undercut its humanitarian bona fides. Trump’s justifications for the Syria strike are thus weaker than those offered for NATO’s use of force in Kosovo during the 1990s, which also lacked Security Council approval.
In short, while preventing further use of chemical weapons is certainly a laudable aim, the strike violates the UN Charter. The strike further underscores a critical insight behind Article 2: that governments are prone to use humanitarian motives as a pretext for intervening in other states and that such intervention can have unforeseen, adverse consequences.
The U.S. strike in Syria also runs afoul of domestic constraints on the use of force, as Marty Lederman has explained. First, because the strike violates the UN Charter, a binding international treaty, it also violates the Constitution’s Supremacy Clause and places the Trump administration in breach of its obligations under Article II’s Take Care Clause. Although Congress could authorize the strike under domestic law, it has not done so (such authorization would not, however, redress the U.S. breach of its international-law commitments). The lack of congressional authorization not only fails to cure the constitutional deficiency resulting from breach of a binding treaty obligation, but also contravenes the constitutional allocation of war powers.
Under more traditional formulations, the president lacks authority to use force unilaterally, except to repel sudden attacks or protect U.S. lives overseas. The War Powers Resolution, moreover, makes clear that no treaty can supply the required congressional authorization for the introduction of armed forces into hostilities, including where the president acts in a UN Security Council approved operation.
More recent practice, however, is cited to support claims of broader presidential authority to use force without congressional approval. The 2011 Office of Legal Council (“OLC”) Memorandum on President Obama’s constitutional authority to use force in Libya, for example, relied on the president’s assessment of the national interest and the limited nature, scope, and duration of the operation, which the Memorandum explained did not amount to war “in the constitutional sense.” The Clinton administration invoked similar rationales for using military force in Haiti and Bosnia during the 1990s without specific statutory authorization. Additionally, the OLC has cited the War Powers Resolution as implicit congressional recognition of presidential authority to conduct individual strikes or short operations by compelling that the president end the deployment of forces after sixty days unless he or she has obtained congressional approval.
Even if one subscribes to a more robust view of presidential power, Trump’s intervention in Syria is on thin ground. The asserted national-security interest is undercut by the fact that U.S. forces are in Syria to fight ISIS, and Assad has shown no intention of attacking U.S. troops. Also, the administration’s claim about preserving regional stability is weakened by the lack of international support for the strike and the absence of a broader strategy to achieve this goal.
Aside from the legal objections, it is important to consider the broader context. The judgment of history might be softened if the strike were to mark the start of a concerted effort by the United States to deter atrocities, alleviate the massive suffering among the estimated 13 million individuals who have fled or been displaced by the conflict in Syria, and bring peace and stability to the region.
But, the strike will more likely prove an early instance in a pattern of belligerent and knee-jerk military actions. As such, it reinforces the continuing importance of a constitutional framework that places limits on the president’s use of force. Securing authorization from Congress is not only important in gaining domestic buy-in, but also provides a buffer against unilateral executive action undertaken without careful consideration of the potential consequences. While the requirement of congressional approval may limit a president’s ability to respond quickly to a humanitarian crisis, it can also protect against rash and ill-informed decisions
History shows that military operations have a logic and life of their own. What may be intended as an isolated action to send a message about a horrific act by a foreign government, such as the use of chemical weapons, can unleash a chain of events that widen a conflict and further destabilize a region—as Obama learned from the failed U.S. intervention in Libya. Constraints on the use of force, both under the Constitution and international law, can help reduce this risk. Those constraints are valuable even for cautious presidents. But, they are that much more important for a president, like Trump, who is prone to aggressive and impulsive behavior, while commanding the most powerful military in human history.
*Professor of law, Seton Hall Law School.