Beyond Sanctions: Building Accountability for Chemical Weapons Use in Sudan

In light of the continued accusations of the use of chemical weapons against Sudan, the United States (US) has stepped up international pressure, imposing a second round of sanctions in 2025. In more recent months, Colombian fighting forces have reportedly supported the Sudanese state against its citizens, heightening existing concerns. The US has also asked the Organisation for the Prohibition of Chemical Weapons (OPCW) to conduct immediate and independent investigations, rejecting Sudan’s offer to conduct the investigations through a national committee.

This arises in the context of one of the world’s most severe humanitarian crises. Since the outbreak of the conflict between the Sudanese Armed Forces (SAF) and the Rapid Support Forces (RSF) in April 2023, hundreds of thousands of people have been killed, millions have been displaced, and the country’s institutions have gradually deteriorated. If proven, the use of chemical weapons would not only constitute a violation of the Chemical Weapons Convention (CWC) but also an assault on one of the long-standing humanitarian principles of international law.

Though sanctions have been the go-to approach for the international community in response to flagrant violations of international law, their efficacy in forcing behavioural change in military regimes is questionable.

The example of Sudan raises a broader policy issue. Though sanctions have been the go-to approach for the international community in response to flagrant violations of international law, their efficacy in forcing behavioural change in military regimes is questionable. In this context, Sudan offers an opportunity to re-examine whether economic pressure alone can bring about accountability or whether other measures are needed.

The Challenge of Independent Verification

The prohibition on chemical weapons use is a long-standing principle of international humanitarian law. In accordance with its obligations under the Chemical Weapons Convention (CWC), the Government of Sudan is forbidden from developing, stockpiling, or using chemical weapons and is required to cooperate with any investigations into credible allegations. The position of the United States of America (US) is that, based on its assessment, there is no doubt that the Sudanese Armed Forces (SAF) used chemical weapons in 2024 during military operations. However, the US did not publish details of the type of chemical weapon used or the scale of its use until media reports identified it as chlorine gas. Sudan, in turn, denies the accusations and has said it will take responsibility for monitoring any alleged use of chemical weapons through a domestically established special investigative committee.

However, the US, along with the broader international community, has highlighted the need to address the situation beyond a domestic investigation, citing the need for independent verification when state institutions are parties to the incident. Such investigations are critical because they affect not only the population’s health but also broader humanitarian operations. Reports of chemical attacks can cause panic, overload the medical system, hinder humanitarian work, and result in the displacement of civilians.

Why Sanctions Alone Fall Short

As a result of these violations, Washington imposed additional sanctions on Colombian fighting forces deployed to Sudan to support the military-backed government after it was determined that the government was no longer in compliance with the Chemical Weapons Convention (CWC). These sanctions are part of a broader set of sanctions that the United States (US), the European Union (EU), and the United Kingdom (UK) have imposed against military officials and military-affiliated entities in Sudan accused of committing atrocities. Sanctions remain an essential tool of international diplomacy, enabling states to condemn violations of international norms without military intervention while imposing political and economic costs on offenders. However, sanctions are often critiqued because they rarely prove sufficient to change the behaviour of military regimes.

The case of Syria illustrates that these sanctions often fail. In light of repeated accusations of the use of chemical weapons by the Assad regime, the United States (US), the European Union (EU), and the United Kingdom (UK) enforced broad sanctions on officials, military structures, and economic interests associated with the regime. Though there was no lack of economic pressure, Organisation for the Prohibition of Chemical Weapons (OPCW) and United Nations (UN) investigations continued to document violations of international law involving the use of chemical weapons. These sanctions created considerable economic and political difficulties for the Syrian government, but it was able to withstand them because of support from countries including Russia and Iran.

Myanmar is another example where sanctions fail to achieve their goals. Following the military coup in 2021, Western countries, including the United States (US), imposed broad sanctions on military officials and the military companies they owned. While the sanctions have isolated the junta diplomatically and restricted its overseas economic activities, they have not resulted in a democratic transition or a decrease in violence against civilians.

In South Africa, however, sanctions helped bring about political change. Sanctions and sporting boycotts against apartheid South Africa increased the cost of its policies. However, they succeeded largely because they were aligned with the country’s already strong domestic resistance, trade unionism, and negotiations for a political transition.

While sanctions remain a useful policy tool, they are more effective at signalling international condemnation and raising the costs of undesirable behaviour than at persuading authoritarian regimes to abandon oppressive practices. Sudan’s circumstances more closely resemble those of Syria and Myanmar than South Africa. The military elite remains engaged in the civil war, controls state institutions, and continues to cultivate new political and economic ties. Under these conditions, sanctions may increase pressure but are unlikely, on their own, to induce behavioural change.

Sanctions should not be viewed as the primary mechanism for accountability but rather as one component of a broader accountability framework.

Beyond Sanctions: A Three-Pillar Strategy

Sanctions should not be viewed as the primary mechanism for accountability but rather as one component of a broader accountability framework. Such a framework for addressing the use of chemical weapons could include:

• Strengthening Independent Verification: The OPCW needs to adapt to the realities of modern warfare. Delays or an inability to access attack sites can compromise evidence and undermine public trust. It would be useful to establish permanent rapid-response investigation teams that could travel swiftly to attack sites. There should also be greater transparency throughout the investigation. The regular release of factual information, without compromising the investigation, can minimise the scope for propaganda

• Investing in Domestic Accountability: A sustainable approach to long-term accountability requires more than international pressure. For sustainable reform to occur, institutions within Sudan must be strengthened to document, preserve, and safeguard evidence of atrocities. The international community must increase its support for Sudanese civil society groups, investigative journalists, legal organisations, doctors, universities, and local documentation projects through funding and technical assistance. These groups often serve as repositories of evidence during conflict and are critical to maintaining trust when state institutions have been destroyed or manipulated. Investment in these groups will help lay the foundations for future transitional justice. In contrast to sanctions, which seek to influence state actors from the outside, investment in civil society strengthens accountability by influencing them from within.

• Linking Pressure to Incentives: Sanctions must also be embedded within a framework of conditional engagement, rather than merely serving as a punitive tool. The conditions should include cooperation with Organisation for the Prohibition of Chemical Weapons (OPCW) inspection missions, safeguarding humanitarian access, adherence to international humanitarian law, and transparency regarding any claims of chemical weapons use. Such an approach would ensure that sanctions do not become a form of indefinite punishment but rather a tool for encouraging behavioural change by linking them to specific legal requirements

Conclusion

The Sudan example illustrates the shortcomings of using sanctions as the sole strategy for responding to crimes against humanity. Sanctions are not the only tool needed to protect the global norm against the use of chemical weapons. Sanctions can be effective, but they must be bolstered by additional tools to ensure compliance by states already in defiance of international norms This requires regular third-party verification, empowering domestic activists and authorities to document and report violations independently, and linking verification mechanisms to meaningful incentives. Effective accountability also requires support for independent civil society, well-functioning international legal institutions, and diplomatic engagement based on both responsibility and incentives. As warfare becomes more fragmented and politically complex, the international system needs to shift away from relying solely on punishing states for their violations. Instead, it should adopt a comprehensive strategy that combines legal enforcement with institutional development.

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Shravishtha Ajaykumar is an Associate Fellow with the Centre for Security, Strategy, and Technology at the Observer Research Foundation.

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