Reviving Chemical Weapons Accountability in a Multipolar World

A week before the 29th Session of the Conference of States Parties of the Organization for the Prohibition of Chemical Weapons (OPCW) in The Hague, the Technical Secretariat of the OPCW issued a report concluding that it had found a riot control agent (RCA) in the trenches in Ukraine. The report is the latest chink in the armor of the Chemical Weapons Convention (CWC), which prohibits the development, stockpiling, and usage of chemical weapons.

Thought to be universally accepted, the norm against chemical weapons use has come under increased strain in the past decade. Cases like Syria’s repeated use against civilians, Russia’s battlefield deployment of chemical agents in Ukraine, and Iran’s reported development of weaponized synthetic opioids reveal an unsettling trend in accountability and enforcement. Some states are testing the limits of the CWC’s capacity to hold violators accountable, while Russia and Iran are exploring new, asymmetrical means of warfare to challenge adversaries.

Next week’s conference presents an opportunity to revitalize efforts toward accountability and global cooperation. The United States, in particular, is in a position to reverse course on the dangerous erosion of the chemical weapons norm and maintain the integrity of the CWC. But to do so, it will need to engage friend and foe alike.

The State of the Chemical Weapons Norm

The chemical weapons norm has become a victim of a new multipolar era. The Assad regime’s usage of sarin and chlorine gas on its own people since the start of the conflict in 2011 brought chemical weapons back to the Middle East for the first time in the post–Cold War era. But it was not a given that Assad would get away with these egregious war crimes a decade ago.

Following a 2013 sarin gas attack that killed over 1,400 people in Ghouta, Syria, international outrage prompted efforts to eliminate Syria’s chemical arsenal with Russia’s cooperation. Yet, accountability for these war crimes has faded from the international spotlight, as has Russian acquiescence to investigate and attribute chemical weapons attacks in Syria. Russia has since protected Syria from accountability and tried to attack and discredit the OPCW.

A decade later, the Assad regime has failed to cooperate with the OPCW on numerous nontrivial issues, including undeclared chemical research, the production or weaponization of unknown quantities of chemical weapons, and significant quantities of chemical warfare agents, precursors, or chemical munitions. In June of this year, the United Nations’ disarmament chief, Izumi Nakamitsu, told the Security Council that 17 of the 24 outstanding issues opened by the OPCW Declaration Assessment Team since 2014 remain unresolved in Syria.

Though Syria has faded from the headlines, Assad’s ongoing impunity for these crimes is rippling throughout the world. Not only has he not been punished for using chemical weapons, but Assad has also won back most of Syrian territory and has reentered the Arab League. In the meantime, some European countries have been sending diplomats back to Damascus. As a recent CSIS study pointed out, his success in the face of such egregious transgressions of international norms may push states to consider using chemical weapons as he did.

Somewhat predictably, international cooperation on arms control and the use of prohibited weapons in war is already beginning to break down. Russia’s transformation on this issue is a case in point. While Putin may be too pragmatic to use nuclear weapons, he has learned from his allies in Damascus that he can test the limits of the international community’s willingness to uphold norms with chemical weapons and other weapons of mass destruction (WMDs). Russia has continued to use chemical weapons in assassination attempts and reportedly used RCAs on the battlefield in Ukraine. And a Washington Post investigation last month showed that Russia has been rapidly expanding a restricted military facility called Sergiev Posad-6, which served as a major research center for biological weapons, including Cold War experimentation with smallpox, Ebola, and hemorrhagic fevers. Russia’s renewed interest in biological weapons, chemical weapons, and the protection of others using them signals that the violation of these most basic of norms is back on the table.

Even Iran, a victim of chemical weapons during the Iran–Iraq war in the 1980s, has been developing and weaponizing synthetic opioids like fentanyl, creating agents that could incapacitate both soldiers and civilians. In a world where its proxy forces are severely weakened, and its nuclear capabilities are in danger, Iran may pursue other avenues of deterrence and compellence if the threat to the regime becomes existential. In this new era, nuclear weapons may be for deterrence, but Assad has proven that chemical weapons can be used for survival.

In the meantime, great power competitors like the People’s Republic of China (PRC) wish to defy and weaken a U.S.-led order. And they have many allies in that campaign across the Global South. Despite these challenges, finding areas where leaders on different sides of this divide could come together to uphold international norms is essential. Just as the Soviet Union and the United States cooperated on nuclear arms control and smallpox vaccines, upholding the chemical weapons norms could be a similar area of cooperation for the United States and, for example, the PRC.

Strengthening the CWC Amid Global Tensions

Members of the CWC should approach this upcoming annual session of the Conference of States Parties with renewed vigor. First, it is crucial that CWC states parties use these meetings to maintain pressure on Syria to comply with its treaty obligations. Calling attention to the November 2023 decision C-28/DEC.12 that calls on states parties to restrict the sale of chemicals and dual-use equipment to Syria is vital.

Where such multilateral efforts are unable to hold perpetrators accountable, individual countries should advance justice. This June, a French appeals court upheld an arrest warrant issued for Syrian president Bashar al-Assad over the use of banned chemical weapons against civilians. France’s efforts to hold Syria accountable for chemical weapons through its own courts should be replicated in other countries to potentially affect the calculus of other leaders considering chemical weapons use. Furthermore, the member states should work to transfer knowledge from the Investigation and Identification Team (IIT), which was established solely for the Syria case, to the OPCW and investigative bodies pursuing accountability in Syria and the unfortunate next case of chemical weapons usage.

States parties could also address the troubling reports of Russia’s use of riot control agents in Ukraine. Despite formal requests for clarification, Russia has yet to respond substantially, even as it accuses Ukraine of using RCAs and attacking chemical facilities on Russian soil. By leveraging the OPCW’s expertise and objectivity and bringing in perspectives from NGOs, legal experts, and scientists, the conference could bolster evidence-based discussions on RCA use, helping to clarify potential violations. It is also crucial that the OPCW continues to call out Russia’s unsubstantiated claims about U.S. support for Ukrainian chemical weapons preparations. These efforts could contribute to the deterrence of chemical weapons use in Ukraine and uphold the integrity of CWC.

The United States is in a good position to lead some efforts, having destroyed its chemical weapons stockpile in 2023. Revitalizing the International Partnership Against Impunity for the Use of Chemical Weapons could be one avenue, but the initiative launched by France in 2018 is missing many powerful members of the international community that have notably not signed on. The United States and its allies in Europe and East Asia cannot do it alone. Advancing accountability and upholding the norm will require more diverse multilateral backing.

Shoring up the CWC will depend on increased cooperation with adversaries like Beijing as well as allies. The current administration has already recognized this and tried to revive bilateral CWC-related meetings. Under Secretary of State for Arms Control and International Security Bonnie Jenkins recently called on China to engage in risk reduction talks with the United States during her remarks at the 19th NATO Conference on Arms Control, Disarmament, and WMDs in Poland. While these conversations are difficult with regard to nuclear weapons, given Beijing’s build-up and U.S. modernization, chemical weapons may be an entry point to restart constructive discussions.

In the past, China has signaled its willingness to engage on these issues. Just this past September, OPCW director-general Fernando Arias met with senior Chinese officials, including representatives from China’s Ministry of Industry and Information Technology, military, and Ministry of Foreign Affairs, as well as the vice mayor of Shanghai. They focused on reforming the verification process to address both security and economic needs while considering the geographic balance to tackle emerging challenges under the CWC.

This Chinese interest in preserving the OPCW and preventing chemical weapons use may stem, in large part, from its historical experience. The Chinese had been victims of chemical warfare during the Second Sino-Japanese War when Japan carried out 375–2,000 chemical attacks that killed tens of thousands from 1937 to 1945. No Japanese officials were prosecuted for chemical weapons use after World War II, and China is still dealing with the abandoned chemical munitions by Japanese forces. However, in the past two decades, Sino-Japanese cooperation to dispose of chemical weapons has been useful for China and Japan’s credibility—even though bilateral tensions have sometimes strained the destruction process. This more positive experience and clear Chinese interest in these issues could also signal that chemical weapons could be a politically feasible area of cooperation between the United States and the PRC.

This approach could not only address chemical weapons issues but, if successful, could also lay the groundwork for broader discussions on WMDs. Talks on nuclear arms control and risk reduction have made little progress in recent years. While the United States has repeatedly extended offers to engage, China has been largely unresponsive or tied conversations to U.S. arm sales to Taiwan, and the countries have only engaged on artificial intelligence and nuclear command. However, following a meeting between U.S. national security adviser Jake Sullivan and senior Chinese officials in Beijing in August 2024, a U.S. official noted that “the conversation is slightly more ripe than it was in 2022.” Discussions on chemical weapons could further build some trust and diplomatic muscle needed to facilitate broader conversations on nuclear weapons and other issues.

It will not be easy, however. China voted in lock step with Russia to protect the Assad regime at the UN Security Council. The incoming U.S. administration also appears to be more hawkish on China, given recent cabinet picks. Still, the new administration will need foreign policy wins and may be obliged to find some areas of cooperation with the second-largest economy in the world.

Renewed cooperation with China on this file could also affect North Korea’s chemical weapons stockpile. While China has been reluctant to use its considerable economic and political influence on North Korea to mitigate Pyongyang’s militaristic behaviors, Beijing could tie essential resources, such as food and energy aid, to North Korea, taking verifiable steps toward dismantling its chemical weapons stockpile. China’s concerns that its relationship is being diluted by the DPRK’s increasing ties with Russia over Ukraine could serve as a strategic incentive for Beijing to regain its leverage while also proving itself to be a more responsible stakeholder in the international community. With its nuclear program, North Korea may also be more amenable to dismantling its chemical weapons program.

A Multilateral Pathway

Finding pathways to reinforce basic norms and arms control in a polarized world is more important than ever. Engagement between the United States and China, driven by shared interests and historical legacies, could reinvigorate international norms against chemical weapons and lay the groundwork for broader WMD dialogues. By uniting to prevent chemical weapons proliferation and use, the international community can help preserve the CWC’s objectives in a changing global landscape, demonstrating the enduring value of and vital need for multilateral cooperation on arms control.

Natasha Hall is a senior fellow with the Middle East Program at the Center for Strategic and International Studies (CSIS) in Washington, D.C. Doreen Horschig is a fellow with the Project on Nuclear Issues at CSIS.