I'll examine Russia's stated justifications for the invasion and how they stand up under international law.
Russia's invasion of Ukraine, launched on February 24, 2022 as a "special military operation," is widely disputed, with Russia offering several justifications that the majority of the international community and international legal experts have rejected.
1. Russia's Stated Justifications
In his February 23-24, 2022 address, President Vladimir Putin claimed that intervention was necessary to:
•Protect Russian speakers in Donbas from "abuse and genocide" - Putin claimed military intervention was necessary to "protect people who have been subjected to abuse and genocide" by the Ukrainian government. This included claims of "bullying and genocide" in Donbas alongside goals of "demilitarisation and denazification of Ukraine".
•Counter threats from NATO and protect Russian security - including claims that Ukraine was developing nuclear weapons and that NATO was building up military infrastructure in Ukraine, threatening Russia, and that Ukraine had to be blocked from joining NATO.
•Collective self-defense at the request of Donetsk and Luhansk - Putin said the Donetsk and Luhansk People's Republics — which Russia had recognized as independent states two days before — had requested assistance in their fight against the Ukrainian government. Russia has argued its use of force is lawful under Article 51 of the UN Charter, which preserves rights to defend against "an armed attack" and to engage in "collective self-defense" to defend those republics.
•Precedent of Western interventions - Russia has compared its actions to interventions by the United States and its allies in conflicts such as the Kosovo War, the Iraq War, the Libyan Crisis, and the Syrian civil war.
2. How International Law Assesses Those Claims
The UN Charter sets the framework for legal use of force:
•Article 2(4) provides that all members "shall refrain in their international relations from the threat or use of force against the territorial integrity or political independence of any state", and Article 2(3) requires states to settle disputes by peaceful means. The only two exceptions enshrined in the Charter are self-defense and authorization by the Security Council.
•Since the beginning, the invasion has been described as violating international law including the Charter of the United Nations.
On the specific Russian arguments:
•Self-defense: Experts including John B. Bellinger III, Gabriella Blum, Naz Modirzadeh and Anthony Dworkin have criticized the Article 51 argument, arguing that Ukraine has not threatened or attacked any other nation and that even if Ukraine had been planning an attack against Donetsk or Luhansk, Russia could not invoke collective self-defense because these regions are not recognized as separate states under international law.
•Genocide / humanitarian intervention: Experts have rejected the humanitarian justification. Commentators have questioned whether international law including the UN Charter and the Genocide Convention even allows nations to use force to remedy genocide, as the legality of humanitarian intervention is heavily disputed. In any event, Russia's humanitarian justifications are widely perceived as a pretext and are unsubstantiated by evidence that Ukraine committed acts against Russians in Donetsk and Luhansk that could amount to genocide. Scholars described Putin's allegations of genocide and comparison of Ukraine to a Nazi state as baseless.
•Comparisons to other wars: Those comparisons have been dismissed as irrelevant because one illegal act does not make a different act legal. Professors noted these arguments "would carry little weight in any court of law" because "even if [they were] true, one illegal use of force does not justify another".
3. International Institutional Response
•Because it violates the UN Charter and is more than a minor border incursion, legal experts qualified the intervention as a crime of aggression under Article 8bis(1) of the Rome Statute, defined as "an act of aggression which, by its character, gravity and scale, constitutes a manifest violation of the Charter of the United Nations".
•The invasion was also said to violate international agreements Russia is party to, including the 1975 Helsinki Final Act, the 1994 Budapest Memorandum in which Russia agreed "to respect the independence and sovereignty and the existing borders of Ukraine," and the Minsk agreements.
•The UN General Assembly condemned the action. Resolution ES-11/1, adopted on 2 March 2022, deplored Russia's invasion of Ukraine and demanded a full withdrawal of Russian forces and a reversal of its decision to recognise Donetsk and Luhansk. It passed with an overwhelming 141-5 vote majority, with 35 nations abstaining.
In summary:
•From Russia's perspective, the invasion was presented as a defensive and humanitarian necessity to protect Russians, prevent genocide, ensure demilitarisation/denazification, and counter NATO expansion.
•From the perspective of most states, the UN General Assembly, and a majority of international law scholars, those justifications do not meet the legal criteria for self-defense or Security Council authorization under the UN Charter, the genocide claims lack credible evidence, and the invasion therefore violates Article 2(4) and constitutes an illegal use of force / act of aggression.
Whether the invasion is "justified" depends on which legal and political framework is applied; under the UN Charter as interpreted by most international courts and legal experts, it is considered not legally justified, while Russia maintains its own stated security and humanitarian rationale.