Did North Korea's Use of VX Nerve Agent Violate International Law?

On February 13, Kim Jong-nam—the half-brother of North Korean leader Kim Jong-un—was killed at the airport in Kuala Lumpur, Malaysia. Malaysian investigators have determined that two women, who have since been charged with murder, used VX nerve agent—a chemical weapon—in the assassination. Attribution has not yet been confirmed, but Malaysian Prime Minister Najib Razak has directly blamed North Korea (DPRK) for the assassination. In addition, U.S. and South Korean officials reportedly believe DPRK is responsible for the killing.

The incident has caused considerable diplomatic escalation between DPRK and Malaysia. Both countries have declared each other’s ambassadors personae non gratae. And after DPRK banned Malaysian citizens from leaving DPRK, Malaysia responded by banning North Koreans from leaving Malaysia—though Malaysia has also decided to deport 50 North Koreans.

In considering possible unilateral U.S. responses to DPRK’s use of a chemical weapon, some have speculated that the U.S. will reinstate DPRK’s status as a state sponsor of terrorism, thus imposing sanctions and conveying a hefty political statement—though the U.S. could otherwise impose sanctions on DPRK without making such a designation. Because VX nerve agent is listed as a Schedule 1 chemical under the Chemical Weapons Convention (CWC), it’s reasonable to ask whether chemical weapons treaties can be leveraged against DPRK, and if not, what other international law mechanisms might be available.

Below is a brief overview of the possibly applicable laws and treaties. In short, DPRK is either not a state party to various agreements that it might otherwise have violated or the agreements to which it is a state party do not apply in this case because it is not in an armed conflict with Malaysia. Consequently, if the United Nations (UN) would like to enact measures against DPRK over this incident, it will have to use a broader legal hook from international law.

1925 Geneva Gas Protocol

The 1925 Geneva Gas Protocol prohibits the “use in war of asphyxiating, poisonous or other gases, and of all analogous liquids, materials or devices.” The treaty only binds states parties “as between themselves,” and both DPRK and Malaysia are states parties to this agreement. But the main problem with using this treaty as the legal basis for a response is that DPRK and Malaysia were likely not in a state of armed conflict—“in war” as the treaty requires—when the incident occurred.

One might try to argue that an assassination conducted by DPRK in Malaysia qualified as an act of aggression, thus triggering a state of international armed conflict. But the Commentary on the Geneva Conventions of 1949 defines armed conflict as “[a]ny difference arising between two States and leading to the intervention of armed forces” regardless of “how long the conflict lasts, or how much slaughter takes place.” And other definitions of international armed conflict involve “a resort to armed force” or a “use of arms” between states. Even if DPRK’s military was involved in the assassination, the isolated nature and limited effects cut against a determination that it triggered a state of armed conflict.

Chemical Weapons Convention

The CWC eliminates the armed conflict requirement. The Convention requires that each state party “[undertake] never under any circumstances:”

(a) To develop, produce, otherwise acquire, stockpile or retain chemical weapons, or transfer, directly or indirectly, chemical weapons to anyone;

(b) To use chemical weapons;

(c) To engage in any military preparations to use chemical weapons;

(d) To assist, encourage or induce, in any way, anyone to engage in any activity prohibited to a State Party under this Convention.

While use of VX nerve agent would be a clear violation, DPRK is not a state party to the CWC. There is, however, a provision in the CWC allowing for the Organization for the Prohibition of Chemical Weapons (OPCW) to cooperate with and dedicate resources to the UN Secretary General when a non-state party uses a chemical weapon. And the OPCW, according to the treaty, can bring matters to the UN Security Council (UNSC) or the UN General Assembly. However, given that DPRK is not a state party and therefore did not violate the CWC, the predicate for any measures imposed by the UN, even upon referral from the OPCW, would have to be a different violation of international law.

Rome Statute of the International Criminal Court

The Rome Statute prohibits states parties from “[e]mploying poison or poisoned weapons” and “[e]mploying asphyxiating, poisonous or other gases, and all analogous liquids, materials or devices” in international armed conflict. A 2010 amendment applies this prohibition to non-international armed conflict, but only for the states parties that have ratified it.

Because neither DPRK nor Malaysia is a state party to the Rome Statute, the International Criminal Court (ICC) can only exercise jurisdiction upon referral from the UNSC or with consent from either Malaysia or DPRK concerning this incident. These methods, however, would be fruitless for multiple reasons. First, the underlying offense requires the existence of armed conflict. Furthermore, as Beth Van Schaack explains in Just Security, the Rome Statute’s drafting history indicates that an explicit prohibition of chemical weapons was intentionally excluded from the treaty, and the provision that the drafters envisioned might eventually cover chemical weapons has so far not been activated. Finally, in deciding whether to investigate, the ICC Prosecutor “must also ascertain whether any national authorities are conducting a genuine investigation or trial of the alleged perpetrators of the crimes.” Presumably, the ongoing Malaysian investigation of the incident would therefore preclude an ICC investigation.

Other Treaties

The two other treaties relevant to chemical weapons would not apply to this VX nerve agent incident.

The 1899 Hague Declaration Concerning Asphyxiating Gases prohibits states parties “from the use of projectiles the sole object of which is the diffusion of asphyxiating or deleterious gases.” This treaty does not apply, though, for several reasons. The agreement pertains only to international armed conflict between states parties, yet DPRK and Malaysia are neither in armed conflict with each other nor states parties. Also, DPRK used VX nerve agent neither as a projectile nor in gaseous form.

The 1907 Hague Convention on the Laws and Customs of War on Land prohibits states parties from “employ[ing] poison or poisoned weapons.” Yet this agreement also applies only to international armed conflict.

As an aside, though DPRK is not a state party to the 1907 agreement, the treaty expresses rules that have since come to be recognized as customary international law (CIL), thereby binding non-states parties as well—but, once again, only in international armed conflict.

Customary International Law on Chemical Weapons

Customary international law, as stipulated by Rule 74 of an International Committee of the Red Cross study, holds that chemical weapons use is prohibited in both international and non-international armed conflict. Where DPRK and Malaysia are not in a state of armed conflict, this aspect of CIL cannot be used as a legal hook for action against DPRK.

Violations Not Directly Related to Chemical Weapons

Outside of chemical weapons violations, the UNSC could address DPRK’s use of VX nerve agent by using other legal bases. For example, the UNSC could—pursuant to Chapter VII, Articles 41 and 42 of the UN Charter—determine that the act constitutes a threat to international peace and security and then impose measures against DPRK. There is, after all, a historical precedent for the UN Security Council deeming the use of chemical weapons as such: UNSC Resolution 2118 “determine[d] that the use of chemical weapons anywhere constitutes a threat to international peace and security.” One could also possibly argue that DPRK’s assassination of a person in foreign territory violated the CIL prohibition of intervention.

The extent to which the UNSC will consider this matter remains uncertain, and it will likely depend on both the outcome of investigations and political considerations. According to an OPCW statement condemning the use of VX nerve agent (but not attributing it to DPRK), the organization will provide assistance, if requested, in Malaysia’s domestic investigation of the incident. In the same statement, the OPCW also “called for those responsible for the use of chemical weapons to be held accountable.”

So far, language from permanent UNSC members has reflected a desire to wait. When the UNSC met last week to consider DPRK’s recent missile launches, it reportedly also raised the DPRK VX nerve agent issue, although the British Ambassador to the UN suggested that “there was not a particular proposal for the Security Council to take any action at this stage.” In addition, the UN Ambassador from China—whose support of or opposition to international measures could prove decisive—said, “The investigation is still going on, I think we need to see how the process will lead and what the true situation is.” Meanwhile, U.S. Ambassador to the UN Nikki Haley offered stronger language: “We absolutely see no place for chemical weapons in any situation whatsoever, so it's incredibly disturbing.”

On Syrian chemical weapons use, Haley offered even tougher language in support of a UNSC resolution that would have imposed sanctions. But that resolution still met vetoes from Russia and China. If the U.S. hopes to work through the UNSC to impose measures against DPRK over its alleged use of VX nerve agent, it might need to use skillful diplomacy to secure China’s support. Several points highlighted by Stephan Haggard in a previous Lawfare post might help in this regard, including increased tension between China and DPRK as well as China’s “[w]illingness to support sanctions that are narrowly targeted at [DPRK’s] WMD program.” And Trump’s decision to honor the “One China” policy was, of course, a helpful step. But Haggard also points out that China’s support for DPRK initiatives could turn, in part, on the Trump administration’s willingness to negotiate instead of deflecting responsibility solely to China. And the administration’s recent cancellation of a planned meeting between a DPRK envoy and former U.S. officials may not bode well for Trump’s broad interest in negotiating on DPRK issues.