The Legality of Russia's Invasion of Ukraine Under International Law

By Ujjwalraj Views: 14865

The full-scale invasion of Ukraine by the Russian Federation in February 2022 stands as a pivotal moment in modern international relations and law. The attack not only shocked the conscience of the global community due to its humanitarian consequences but also represented an unprecedented violation of the long-standing international legal order. The use of military force against a sovereign state, without justification grounded in international law, undermines the very principles upon which the United Nations was founded.

In this context, one essential question dominates discussions among legal scholars, policymakers, and institutions worldwide: Was Russia's invasion of Ukraine legal under international law? A thorough examination of the United Nations Charter, customary international law, international court rulings, and global state practice yields a definitive conclusion-Russia's actions represent a flagrant breach of international legal norms, especially those concerning state sovereignty, territorial integrity, and the prohibition on the use of force.

Under the framework of international law established after the devastation of World War II, the prohibition of the use of force by one state against another is foundational. This principle is most explicitly articulated in Article 2(4) of the United Nations Charter, which prohibits "the threat or use of force against the territorial integrity or political independence of any state." Recognized as a peremptory norm-or jus cogens-this prohibition is non-derogable and universally binding.

Exceptions to this rule are extremely limited. Article 51 of the UN Charter permits self-defence only in response to an armed attack, and Chapter VII authorizes collective action through the UN Security Council to restore peace and security. Neither of these exceptions applied to Russia's invasion. Ukraine did not launch an armed attack against Russia, and the Security Council did not authorize any use of force. Russia's military campaign, therefore, represents a unilateral and illegal use of force, in direct contradiction to the established legal framework governing international relations.

Despite the apparent illegality of its actions, Russia has attempted to craft several legal justifications, though none withstand close scrutiny. One prominent claim by Moscow was the need to protect ethnic Russians and Russian-speaking populations in eastern Ukraine, alleging that these groups were facing persecution and even genocide. Russia referred to the Genocide Convention and hinted at a humanitarian intervention rationale.

However, humanitarian intervention-though discussed in academic and policy circles-is not a legally recognized exception to the prohibition on the use of force. More importantly, no credible international organization or observer, including the United Nations or independent human rights monitors, found any evidence of genocide in Ukraine.

When Ukraine brought a case to the International Court of Justice (ICJ) under the Genocide Convention, the Court issued provisional measures in March 2022, ordering Russia to halt its military operations. The ICJ found no substantiation for Russia's genocide claims, further eroding the credibility of its legal narrative and reinforcing the principle that unproven or fabricated allegations cannot justify the use of force.

Another defence Russia has invoked is its supposed right to self-defence in light of NATO's eastward expansion and Ukraine's deepening ties with the West. This claim hinges on an interpretation of anticipatory or pre-emptive self-defence, arguing that Ukraine and NATO posed a looming threat to Russian security. However, customary international law and precedent from the ICJ clarify that the right to self-defence under Article 51 only arises in response to an actual or imminent armed attack.

The 1986 Nicaragua v. United States judgment firmly established that vague threats or ideological adversaries do not fulfil the legal threshold for invoking self-defence. Ukraine, at the time of the invasion, had not attacked Russia or even taken hostile military steps toward it. NATO, being a defensive alliance, posed no active military threat to Russia. Even if Ukraine's potential NATO membership presented political discomfort to Russia, discomfort does not equal justification under international law. The anticipatory self-defence doctrine, to the extent it is accepted, demands a threat so immediate and overwhelming that no other means of resolution exist. No such condition was met. Russia's interpretation of Article 51 stretches legal reasoning beyond its limits and has been widely rejected by the legal community as untenable.

In the days leading up to the invasion, Russia took further steps to set the stage for its actions by recognizing the self-declared Donetsk People's Republic (DPR) and Luhansk People's Republic (LPR) as independent entities. Subsequently, it signed mutual assistance treaties with these regions, claiming that it had been invited to intervene militarily.

This maneuver, however, is legally flawed on multiple fronts. Firstly, the recognition of breakaway regions within another sovereign state does not establish a legal basis for intervention, particularly when such recognition occurs unilaterally and without broad international endorsement. The principle of territorial integrity, emphasized in both the UN Charter and key instruments like the 1970 Declaration on Principles of International Law and the 1975 Helsinki Final Act, remains paramount. Although the right to self-determination is recognized in international law, it does not grant regions within states an automatic or unilateral right to seced especially not when secession is not a result of widespread democratic will or egregious violations of human rights.

The so-called referenda in the DPR and LPR were conducted in conditions lacking transparency, oversight, and freedom from coercion, with Russian military forces occupying the region. Therefore, any "invitation" extended to Russia by these entities lacks legitimacy and cannot serve as a legal basis for military action.

The precedent for such actions was already set in 2014 when Russia annexed Crimea. That annexation was carried out under similar pretexts, with a hastily organized referendum held in the presence of Russian troops. Although Russia justified the annexation using the principle of self-determination, the global community overwhelmingly rejected this narrative. United Nations General Assembly Resolution 68/262 affirmed Ukraine's sovereignty and declared the Crimean referendum invalid.

The principle that territory cannot be acquired by force is foundational in international law and was directly violated in Crimea. Russia's replication of this strategy in 2022 through orchestrated referenda in parts of Donetsk, Luhansk, Zaporizhzhia, and Kherson under similar coercive conditions only underscores the continuity of its illegal conduct. The right to self-determination must be exercised in a free and genuine manner, which is impossible under foreign military occupation and in the absence of impartial legal frameworks.

From a broader perspective, Russia's conduct represents a challenge not just to Ukraine but to the integrity of the entire international legal system. One of the central goals of the post-World War II order, as embodied in the UN Charter and reinforced by the Nuremberg Principles, is to eliminate wars of aggression. The crime of aggression, defined in Article 8 bis of the Rome Statute of the International Criminal Court (ICC), criminalizes the planning, initiation, or execution of an act of aggression that constitutes a manifest violation of the UN Charter.

Although Russia is not a party to the Rome Statute, its actions still violate customary international law norms against aggression. Furthermore, the ICC retains jurisdiction over war crimes and crimes against humanity committed in Ukraine, thanks to Ukraine's 2014 and 2015 declarations accepting jurisdiction. The issuance of arrest warrants by the ICC in March 2023 for President Vladimir Putin and his Commissioner for Children's Rights, related to the deportation of children from occupied Ukrainian regions, illustrates that individual accountability for international crimes is increasingly being pursued. These charges not only highlight the human rights violations associated with the invasion but also add a layer of criminal liability to Russia's leadership.

The international community's response further reflects the recognition of the invasion's illegality. The UN General Assembly has passed several resolutions, including ES-11/1and ES-11/4, which unequivocally condemn Russia's actions and call for the immediate withdrawal of its forces. While such resolutions are not legally binding, they reflect a strong consensus on the unacceptability of Russia's conduct.

Outside the UN, a wide array of states have implemented severe economic sanctions, provided extensive military and humanitarian aid to Ukraine, and pursued efforts to diplomatically isolate Russia. The strength and unity of this response are indicative of the global commitment to uphold the core tenets of international law. Even in an era marked by geopolitical rivalries and differing worldviews, there remains near-universal agreement that aggression cannot be tolerated or legitimized.

Yet, the implications of this conflict stretch beyond legality into the broader realm of international order and enforcement. Russia's invasion tests the resilience of the rules-based system established over the past century. If powerful states can flout international law by manufacturing justifications and acting with impunity, the credibility of international institutions is at risk. Legal norms require not only codification but also adherence and enforcement, particularly when violated by influential actors.

The continued war in Ukraine, along with the legal and diplomatic battles waged in its shadow, signals the urgent need to strengthen global mechanisms for accountability and prevention. Without such reform, the deterrent value of international law may be severely weakened, inviting further destabilization.

Ultimately, Russia's invasion of Ukraine is not merely a geopolitical maneuver or military confrontation-it is a profound and systematic violation of international law. It breaches the UN Charter, abuses principles of self-determination and self-defence, and undermines the legitimacy of the Genocide Convention. The legal justifications offered by the Kremlin are riddled with inconsistencies and fail to meet any of the stringent requirements under international law.

The international community's overwhelming condemnation and its legal, economic, and political responses affirm that Russia's actions are both unlawful and unacceptable. Nonetheless, the endurance of the conflict underscores the limitations of current legal structures in preventing or halting such violations when they are committed by major powers. Going forward, a renewed commitment to the international legal order-backed by stronger enforcement mechanisms and collective political will-is essential to preserve a world where peace, sovereignty, and law prevail over force, coercion, and impunity.

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