The images of civilians, particularly children, being asphyxiated by chemical substances and dying in Idlib Province of Syria on April 4 were a game changer. Judging that the chemical attack was carried out by the Syrian government, the United States, two days later, attacked Syria’s Shayrat airbase with 59 Tomahawk cruise missiles.
The US action divided world opinion, and the debate continues on the legality of the unilateral use of force, as it has far wider implications not just in Syria but also elsewhere in the world, particularly when tensions are rising over North Korea.
The use of force is permitted under international law in three circumstances: individual self-defense, collective self-defense and enforcement of resolutions under Chapter 7 of the United Nations Charter. The US justified its use of force on April 7 to deter further use and potential proliferation of banned chemical weapons by Syria. In his letter to US Congress on April 8, President Trump also indicated that he had acted “in the vital national security and foreign policy interests of the United States.”
As chemical weapons were used against civilians, the US action was also intended to avert “a worsening of the region’s current humanitarian catastrophe.” It therefore can be considered a humanitarian intervention.
Can the US justify its actions by the argument of self-defense? That is questionable, given that the Syrian action was not targeted at the US. Allowing the use of banned chemical weapons with impunity, however, could destabilize the international regime banning chemical weapons, which could threaten the national security of not only the US but also of others’. This is a matter of serious concern to the international community.
The legality of humanitarian intervention is upheld under the concept of the “responsibility to protect,” which was endorsed by the World Summit in 2005. Such intervention is allowed when dealing with war crimes, crimes against humanity, genocide and ethnic cleansing. The concept of R2P, as it’s known, was first applied to Libya in 2011, when the UN Security Council, referring to the “responsibility to protect” in its resolution, authorized humanitarian intervention by the international community. The use of banned chemical weapons in Syria could constitute a war crime.
The US attack on April 7 was not based on a Security Council resolution. Those who opposed such intervention called the US action illegal under international law. Russia, which supports the Bashar al-Assad regime of Syria, even called it an “act of aggression.” Yet many Western countries and Japan expressed their political support of the US aerial attack. They considered it necessary because the use of chemical weapons constitutes a violation of international obligations, and further use of banned chemical weapons should be deterred.
Furthermore, Syria violated its own obligations emanating from the Chemical Weapons Convention, which it had signed and ratified. The US also noted that Russia, which guaranteed that no more chemical weapons existed in Syria, was either complicit or incompetent by failing in its responsibilities under the 2013 agreement.
In acceding to the Convention, Syria agreed to eliminate its chemical weapons in 2013 to avoid US airstrikes. The Convention prohibits not only the development, production, storage and use of chemical weapons but also obliges the relevant parties to destroy all their stockpiles. The chemical weapons that Syria possessed were eliminated by the UN and the Organization for the Prohibition of Chemical Weapons (OPCW), in collaboration with the US and other countries.
Still, there were suspicions that the Syrian declaration of its chemical weapons might not have been done fully. There have since been reports of the use of chlorine. Chlorine is a chemical also used to cleanse water for drinking, so its civilian use was not banned. In the April 4 chemical attack, sarin or a sarinlike substance is suspected to have been deployed. Sarin is much more potent than chlorine.
According to the Chemical Weapons Convention, when serious violations occur, the Conference of Parties to the Convention may refer the case to the UN General Assembly and the Security Council. This aligns with customary international law. When international treaties are violated, the Security Council becomes a means of last resort. But since Russia holds a veto power in the Council, the Council will most likely not come to an agreement suppressing the use of chemical weapons in Syria.
Before the US attack, the US, Britain and France drafted a Security Council resolution to force Syria to cooperate fully with the investigation by the OPCW and the UN on the chemical weapons attack. If such cooperation was not forthcoming, the Council would take an enforcement action under Chapter 7 of the UN Charter, in accordance with Security Council resolution 2118 of 2013, as Syria’s use of chemical weapons was considered a violation of the Council resolution.
Russia rejected the demand and drafted its own resolution, trying to weaken the three-party draft by simply asking the investigation to collect and submit evidence on the use of chemical weapons. The 10 nonpermanent members of the Security Council also prepared a draft, aiming to find a middle ground between the two drafts. Before the drafts were even put to a vote, the US acted militarily, as it was clear that no effective action would be enacted by the Council because of a Russian veto threat.
The use of force without first obtaining authorization from the Security Council, except in self-defense, is deemed illegal. Yet there is a precedent when military intervention was justified and went ahead without such authorization. That was the NATO airstrike against the Federal Republic of Yugoslavia (now Serbia) in 1999, when Yugoslavia suppressed the Albanian Kosovars in Kosovo, a province of Yugoslavia then.
The NATO action was justified because of the prospect of no action in the Security Council due to a Russian veto and the urgent need for humanitarian protection of vulnerable people on the ground. NATO’s move was seen as an exceptional step, and later it was more or less accepted as justifiable. In the Syrian case, the US has viewed its action as measured and proportional, in response to the banned use of chemical weapons.
International law is upheld when sovereign states observe it. It can also be interpreted differently in the context of international politics. In a globe where no world government exists, how to protect international norms depends on who can enforce them and the dynamics of world politics.