This contested question draws competing legal and historical claims — I'll gather the stated justifications and the international response to give you a balanced overview.
Russia's invasion of Ukraine, launched on 24 February 2022, is evaluated differently depending on the framework used - Russian government justifications versus international law and the position of most states and international bodies.
Russia's Stated Justifications
In a televised address on 23-24 February 2022, President Vladimir Putin announced a "special military operation", stating its purpose was:
•to support the Russian-backed breakaway republics of Donetsk and Luhansk, whose forces had been fighting Ukraine in the war in Donbas since 2014
•to protect people who have been subjected to abuse and genocide by the Ukrainian government and to "protect Russia and our people"
•to carry out the "demilitarisation and denazification of Ukraine"
His stated reasons as summarized include:
•Protecting the Donetsk and Luhansk separatist regions
•“Demilitarising and denazifying” Ukraine
•Preventing genocide against Russian-speaking minorities in the Donbas
Russia has also framed the invasion in legal terms as lawful under Article 51 of the UN Charter, which preserves rights to individual and collective self-defense. Specifically, Russia recognized Donetsk and Luhansk as independent states on 21 February 2022 and then claimed it was acting on their invitation in collective self-defense.
An additional security rationale cited by Moscow was NATO expansion and closer ties between Ukraine and Western militaries, which Moscow framed as a preemptive military necessity to prevent Western power projection onto the Russian frontier and as a claim that its security interests justify the war.
International Law and International Response
The dominant view among international legal scholars, international courts, and bodies is that the invasion violates international law:
•The invasion has been described as violating international law including the Charter of the United Nations.
•The most cited provision is Article 2(4) of the UN Charter, which declares that member states “shall refrain in their international relations from the threat or use of force against the territorial integrity or political independence of any State”. Article 2(4) provides that all members shall refrain from the threat or use of force against the territorial integrity or political independence of any state, and Article 2(3) requires settlement of disputes by peaceful means. The only two exceptions enshrined are self-defense and authorization by the Security Council.
•Many experts have opined that the invasion violated Article 2(4) and have generally rejected Russia's official legal justifications.
Specific rejections of Russian legal arguments include:
1.Collective self-defense: Experts argued Russia cannot rely on self-defense because Ukraine has not threatened or attacked any other nation, and Donetsk and Luhansk are not recognized as separate states under international law, so Article 51 cannot be invoked.
2.Genocide / humanitarian intervention: Experts have rejected the argument that the invasion is justified to protect Russian-speakers, noting the legality of humanitarian intervention is heavily disputed and Russia's humanitarian justifications are widely perceived as pretext and unsubstantiated by evidence of genocide. Scholars described Putin's allegations of genocide and comparison of Ukraine to a Nazi state as baseless, and his claim that the Ukrainian government were neo-Nazis committing genocide as baseless.
3.Comparisons to Western interventions: Russia's comparisons to interventions such as Kosovo, Iraq, Libya and Syria have been dismissed as irrelevant because one illegal act does not make a different act legal.
4.Security interests: The claim that security interests justify war is also rejected under the Charter framework, which does not recognize such an exception.
Russia also argued that even if the invasion was provoked, this does not make it legal according to international law, a distinction made by legal analysis.
United Nations Votes
•The UN Security Council voted on a resolution to condemn the invasion, but it was vetoed by Russia.
•The UN General Assembly then adopted resolutions condemning the invasion. On 28 February-2 March 2022, a resolution condemning the invasion and demanding withdrawal was passed with an overwhelming 141-5 vote majority, with 35 abstentions. Another tally describes the March 2022 resolution deploring Russia's aggression as passing by 141 votes to five, with 35 abstentions.
•The Assembly also declared that Russia's staged referendums and attempted annexation of four Ukrainian regions have no validity under international law.
The invasion has also been qualified by legal experts as a crime of aggression under Article 8bis(1) of the Rome Statute, defined as an act of aggression which constitutes a manifest violation of the Charter.
Summary
•From Russia's perspective, the operation is presented as justified as defense of Russians in Donbas, prevention of genocide, denazification/demilitarization, and collective self-defense of Donetsk and Luhansk, plus protection against NATO expansion.
•From the perspective of international law as interpreted by the UN General Assembly, the International Court of Justice, and the majority of international legal scholars, the invasion violates the UN Charter's prohibition on the use of force, the claimed Article 51 justification fails because there was no armed attack by Ukraine and Donetsk/Luhansk are not recognized states, and the genocide/humanitarian claims are unsubstantiated and not a lawful basis for force.
Whether the invasion is considered "justified" therefore depends on whether one accepts Russia's factual and legal claims or the prevailing interpretation of international law, which holds the invasion to be illegal.