International Law in Crisis: The Ukraine War and the Failure of Legal Mechanisms

Introduction

Public international law serves as a critical framework for balancing the protection of human rights and the maintenance of global peace. Its role in regulating armed conflicts and ensuring accountability for violations is essential for a just international order. However, the ongoing war in Ukraine has exposed significant flaws and limitations within this system, highlighting a profound crisis in international law. Despite the existence of established legal mechanisms and institutions, their inability to effectively address the conflict raises urgent questions about the efficacy of international law in managing contemporary crises. This article examines how the war in Ukraine has underscored the failures of key legal mechanisms, from the paralysis of the United Nations Security Council (UNSC) to the enforcement challenges faced by the International Criminal Court (ICC). The analysis reveals that these failures are not merely isolated shortcomings but symptoms of a deeper systemic crisis in international law.

Legal Frameworks Governing War and Human Rights

Public international law has long sought to regulate armed conflicts through a series of treaties and conventions aimed at limiting the impacts of war on both combatants and civilians. Key instruments such as the Geneva Conventions and the UN Charter establish rules for conduct during conflicts, emphasising principles of proportionality, distinction, and the prohibition of targeting civilians. These laws are underpinned by core principles of sovereignty, non-intervention, and the responsibility of states to protect human rights within and beyond their borders. However, the effectiveness of these principles often hinges on the willingness of states to comply and the capacity of international institutions to enforce compliance. The war in Ukraine lucidly illustrates the challenges in balancing state sovereignty with the international community’s obligation to prevent mass atrocities.
The United Nations plays a central role in maintaining international peace and security, with the Security Council holding the authority to sanction interventions and peacekeeping missions. However, the UNSC’s decision-making power is often undermined by the veto system, which allows any of the five permanent members (P5) to block resolutions regardless of the severity of the crisis. The International Criminal Court (ICC) is another crucial institution, tasked with prosecuting individuals for war crimes, genocide, and crimes against humanity. However, its jurisdiction is limited to member states and situations referred by the UNSC, creating significant gaps in accountability. Meanwhile, regional bodies like the European Union (EU), NATO, and the Organization for Security and Co-operation in Europe (OSCE) play supplementary roles, focusing on regional security and legal enforcement. Yet, their influence is similarly constrained by political and legal limitations.

Legal Mechanisms in Action: Russian war against Ukraine

The UNSC’s role in responding to the war in Ukraine has been paralysed by the veto power of Russia, a permanent member. Despite clear evidence of mass atrocities and widespread condemnation, the Security Council has been unable to pass binding resolutions to stop the aggression or authorise collective measures. This legal deadlock has sparked debates over reforming the veto system, particularly proposals to limit or suspend veto rights in situations involving mass atrocities.

One potential reform is expanding the number of permanent members to include states such as Germany, Japan, India, and Brazil, who have long sought a seat at the table. However, fierce opposition from existing P5 members makes this unlikely. A more feasible approach may be to limit the scope of the veto, as advocated by the Non-Aligned Movement, by waiving it in all proceedings under Chapter VI of the UN Charter, which addresses the peaceful settlement of disputes. Another promising reform, endorsed by the African Union and states like Italy, Mongolia, Singapore, and Tunisia, suggests that a veto should only block a resolution if cast by two or more permanent members simultaneously. This would significantly curb the power of a single state to unilaterally obstruct international action.

However, some legal scholars argue that the veto system itself does not necessarily need reform but rather a re-evaluation of how it is exercised. Anne Peters suggests that using the veto to shield a nation’s own manifestly illegal actions constitutes an abuse of jus cogens norms, thereby creating a legal responsibility for all Security Council members to treat such vetoes as invalid. This interpretation suggests that rather than amending the UN Charter, legal arguments could be made to challenge and delegitimise abusive vetoes in specific cases, such as Russia’s repeated use of its veto concerning Ukraine. If widely accepted, this approach could shift the focus from structural reform to enforcing accountability under existing legal frameworks, providing a pragmatic alternative to overcoming deadlock in the Security Council.

These reforms, if implemented, could enhance the UNSC’s effectiveness by reducing the ability of a single nation to stall urgent humanitarian or security interventions. While political resistance remains a challenge, refining the veto system in a way that balances power among member states in order to prevent deadlock is essential for a more just and responsive international legal order.

The current impasse reflects a broader issue within international law: the disproportionate power of P5 members and the lack of effective checks on their actions. In response to the crisis, the ICC opened investigations into alleged war crimes and crimes against humanity committed in Ukraine. While this move was significant, the ICC faces substantial challenges, including limited jurisdiction, difficulties in securing cooperation from non-member states, and the practical hurdles of enforcing arrest warrants in active conflict zones. The court’s reliance on state cooperation further weakens its ability to hold perpetrators accountable, highlighting the need for enhanced enforcement mechanisms.

Another notable issue regarding the ICC’s jurisdiction in Ukraine is the country’s recent ratification of the Rome Statute while invoking Article 124. This provision temporarily exempts Ukrainian nationals from ICC jurisdiction over war crimes. Ukrainian officials justify this decision as a means to prevent discrediting the country's political and military leadership, avoiding potential distrust and demoralisation among soldiers. However, this move has drawn considerable criticism, with claims that it reinforces concerns about the selective application of international criminal law—where states support accountability for foreign actors while shielding their own nationals from prosecution. This selective enforcement raises broader questions about the legitimacy of Article 124 and whether its existence undermines the credibility of the ICC and international criminal law as a whole.

Another significant critique relates to whether the ICC’s sole reliance on criminal sanctions is the most effective means of promoting international peace. Some scholars argue that alternative justice mechanisms, such as truth commissions, should be incorporated into the ICC’s framework. These mechanisms offer amnesty to wrongdoers who confess while facilitating reconciliation rather than punishment. This approach has been successful in post-conflict societies, raising questions about whether an expanded mandate for the ICC could improve long-term stability.

Beyond concerns of jurisdiction and enforcement, the ICC also faces the challenge of sustaining legitimacy in a fragmented international legal environment. As efforts to expand the Court’s reach intersect with geopolitical sensitivities, tensions emerge between global accountability and national sovereignty. Attempts to broaden the scope of prosecutions—particularly involving non-party states—risk provoking political backlash, which may further erode the Court’s authority and cooperation base. Ukraine’s decision to invoke Article 124 of the Rome Statute, thereby delaying the ICC’s jurisdiction over its nationals, illustrates how states navigate these tensions to preserve domestic political stability. While such decisions may be framed as necessary for national morale and cohesion during wartime, they also highlight the uneven and politically fraught landscape in which the ICC operates. This reality underscores the need to rethink how legitimacy and consistency can be preserved without overreaching the institutional limits imposed by international politics.

Moreover, some criticisms of the ICC appear to be politically motivated efforts to undermine the court’s role in upholding justice. While legitimate concerns about bias and enforcement exist, it is essential to distinguish these from attempts to delegitimise the institution altogether. Recognising and addressing both well-founded critiques and politically motivated attacks is crucial for strengthening the ICC’s role in delivering justice and ensuring accountability for international crimes.

The Responsibility to Protect (R2P) doctrine was designed to prevent mass atrocities when national governments fail to do so. In theory, R2P could provide a legal basis for intervention in Ukraine to halt crimes against civilians. However, the doctrine’s implementation is blocked by concerns over violating state sovereignty and the UNSC’s veto gridlock. R2P is structured around three pillars: the responsibility of a state to protect its own population, the responsibility of the international community to assist states in fulfilling this duty, and the obligation to take collective action when a state manifestly fails to protect its citizens. Given the reports of war crimes and crimes against humanity in Ukraine, the third pillar could, in principle, justify military intervention if diplomatic measures and sanctions prove insufficient. Yet, the current impasse at the UNSC highlights a broader dilemma—should the international community prioritise state sovereignty over the urgent need to prevent mass atrocities?

While intervention under R2P is generally considered a last resort, its effectiveness is undermined if the doctrine is rendered inoperable due to political considerations. Some legal scholars argue that humanitarian actors should advocate for an interpretation of the UN Charter that prioritises human rights protection over rigid adherence to sovereignty. Others suggest that bypassing the UNSC through alternative coalitions, such as regional organisations or an alliance of willing states, may be necessary in cases where immediate action is required. This debate underscores the pressing need to clarify R2P’s legal standing and operational mechanisms to ensure it remains a viable tool for preventing mass atrocities.

The failure to operationalise R2P in Ukraine exposes a fundamental contradiction within international law: the tension between respecting sovereignty and protecting human rights.

Reforming International Law to Address Future Conflicts

Reforming the UNSC’s veto system has emerged as a crucial step toward revitalising international law. Proposals include limiting veto use in cases of genocide and mass atrocities, as well as requiring an explanation for vetoes exercised in such contexts. Limiting the veto in this way would be pragmatic because it addresses the primary obstacle to effective Security Council action—unilateral obstruction by a single state—without completely dismantling the power dynamics of the UNSC. By narrowing the circumstances in which the veto can be exercised, such as prohibiting its use in cases of mass atrocities, the reform would create a balance between the need for decisive action and the interests of powerful states.

Additionally, requiring permanent members to justify their vetoes could introduce greater transparency and accountability, discouraging the arbitrary use of veto power. Such a reform would ensure that national interests do not take precedence over international humanitarian imperatives. While P5 members may resist these changes, incremental reforms—such as those recommended by the Accountability, Coherence, and Transparency (ACT) Group, which advocates for voluntary restraint in veto use—could serve as a starting point for broader structural adjustments. Ultimately, these measures would enhance the credibility and functionality of the UNSC, preventing legal paralysis while still preserving the Council’s authority in international governance.

The failure of the League of Nations—the first major international organisation created in the aftermath of World War I—offers a sobering precedent for the current crisis facing the United Nations. Despite its ambitious goals, the League ultimately collapsed due to its inability to prevent aggression, enforce collective security, or maintain the confidence of its members. Its structural weaknesses, particularly the lack of an effective enforcement mechanism and the inability to act decisively in the face of rising militarism, rendered it irrelevant in the lead-up to World War II. Today, the UN risks following a similar path. The continued paralysis of the Security Council, especially due to the misuse of the veto power by permanent members, undermines the organisation’s legitimacy and effectiveness. If left unreformed, this dysfunction could erode global trust in the UN, leading to its marginalisation or even collapse as a credible institution. Much like the League of Nations before it, the UN’s inability to adapt to contemporary security challenges and uphold the principles of the international legal order may ultimately threaten its very existence.

Enhancing the enforcement capacity of the ICC is equally important. Legal mechanisms such as broader state cooperation frameworks, financial independence for the court, and a streamlined process for issuing and executing arrest warrants could significantly bolster accountability for war crimes. Additionally, establishing a standing UN force for arresting indicted individuals could mitigate enforcement challenges. This force would need to be governed under the direct authority of the United Nations, potentially operating under the Department of Peace Operations to ensure neutrality and adherence to international law. It could consist of personnel contributed by member states, trained specifically for law enforcement in conflict zones, and operate under strict mandates to prevent political misuse. Governance mechanisms would have to include oversight by an independent judicial body to ensure compliance with international legal standards and human rights protections. While politically challenging, such a force could play a critical role in addressing enforcement gaps that currently weaken the ICC’s effectiveness.

Finally, empowering regional organisations like NATO, the EU, and OSCE to take a more active role in enforcing international law could address enforcement gaps left by the UNSC and ICC. This could involve granting these organisations the authority to coordinate international tribunals, assist in evidence collection for war crimes prosecutions, and facilitate the implementation of sanctions against violators of international law. Additionally, these regional bodies could develop specialised task forces focused on humanitarian intervention and rapid deployment in crisis zones, reducing reliance on the UNSC for immediate action. Expanding their mandates and resources would require legal reforms and political consensus, but doing so could ensure a more agile and effective enforcement mechanism while managing the risks of fragmented global governance.

Conclusion

The war in Ukraine has illuminated profound and systemic flaws in the existing international legal structure. From the United Nations Security Council's paralysis in the face of mass atrocities, to the International Criminal Court’s limited jurisdiction and enforcement capabilities, it is clear that the current framework struggles to meet the demands of modern global crises. These institutional failures are not isolated—they reflect deeper structural imbalances and outdated mechanisms that hinder the international community’s ability to uphold peace, justice, and accountability.

The persistent misuse of the veto power by permanent members of the UNSC, particularly in situations involving war crimes and crimes against humanity, has made clear that without reform, the Council risks becoming obsolete. Proposals such as limiting veto use in cases of mass atrocities, requiring justification for its use, or introducing voluntary restraints—like those advanced by the ACT Group—are necessary first steps toward restoring the Council’s credibility and functionality. Without such measures, the UNSC may follow the same trajectory as the League of Nations: weakened by inaction, eroded by mistrust, and ultimately replaced or sidelined.

Similarly, the ICC’s effectiveness is undermined by its reliance on state cooperation, selective jurisdiction, and limited enforcement powers. Without the ability to ensure the arrest and prosecution of perpetrators, the promise of international criminal justice remains largely aspirational. Expanding legal frameworks for cooperation, securing financial and institutional independence, and exploring mechanisms like a standing UN arrest force—however politically complex—must become part of a broader strategy to close the enforcement gap.

At the same time, regional organisations like NATO, the EU, and the OSCE must be empowered to play a more active role in international legal enforcement and humanitarian response. Their strategic position, and operational agility make them valuable partners in addressing legal gaps left by global institutions. Strengthening these regional bodies requires both legal innovation and political will, but such efforts are essential to building a more flexible and responsive international legal system.

Ultimately, the war in Ukraine is a test for the resilience of international law. The failure to effectively address aggression and mass atrocities not only undermines trust in global institutions—it also signals to would-be violators that international norms can be ignored without consequences. To preserve the legitimacy and authority of the international legal order, the global community must commit to meaningful reform. This includes redefining the balance between sovereignty and humanitarian protection, reinforcing enforcement capacities, and ensuring that international institutions remain fit for purpose in the 21st century.

Without such comprehensive reforms, the world risks returning to an era of unchecked violence, political impunity, and institutional irrelevance. The time to act is now—not only to respond to the war in Ukraine, but to secure a more just, accountable, and peaceful international order for future generations.

Kamilla Ladna

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Legislation

ACT Group Code of Conduct regarding Security Council action against genocide, crimes against humanity or war crimes (2015)

Charter of the United Nations (adopted 26 June 1945, entered into force 24 October 1945) 1 UNTS XVI

Charter of the United Nations, Chapter VI
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Rome Statute of the International Criminal Court (adopted 17 July 1998, entered into force 1 July 2002) 2187 UNTS 90

Rome Statute of the International Criminal Court, art 124

Vienna Convention on the Law of Treaties (adopted 23 May 1969, entered into force 27 January 1980) 1155 UNTS 331, art 53

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