I'll examine the legal and political arguments surrounding the invasion, gathering perspectives from stated justifications and international responses.
Russia's 2022 invasion of Ukraine is evaluated differently depending on whether the criteria is Russia's stated justifications or international law and the position of the majority of states in the United Nations.
Russia's Stated Justifications
On 23-24 February 2022, President Vladimir Putin announced a "special military operation" in Ukraine. The stated aims included "the demilitarisation and denazification of Ukraine".
Other stated reasons included:
•Claiming it was necessary to "protect people who have been subjected to abuse and genocide" by the Ukrainian government, and to protect Russian-speaking populations in the Donbas and to protect the Donetsk and Luhansk separatist regions.
•Claiming to act in collective self-defense under Article 51 of the UN Charter on behalf of the Donetsk People's Republic and Luhansk People's Republic, which Russia had recognized as independent states two days before. Russia argued its use of force is lawful under Article 51, which preserves rights to self-defense and collective self-defense.
•Security concerns related to NATO expansion, with Russia citing NATO's expansion into former Warsaw Pact countries, the 2008 Bucharest declaration, and Ukraine's deepening ties with Western militaries as crossing its "red lines" and framing the invasion as a preemptive necessity to prevent Western power projection onto its frontier.
•Comparing its actions to interventions by the US and its allies in Kosovo, Iraq, Libya and Syria.
International Legal Assessment and Responses
The invasion has been widely described as violating international law, including the Charter of the United Nations, and that it violated the Charter precisely because it violated its prohibition on the use of force.
Under the UN Charter:
•Article 2(4) provides that 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 settlement of disputes by peaceful means. The only two exceptions are self-defense and authorization by the Security Council.
•Many experts on international law have said the invasion violated Article 2(4)'s prohibition on the use of force and have generally rejected Russia's official legal justifications.
Specific rejections of Russia's legal arguments include:
•Self-defense: Experts such as John B. Bellinger III, Gabriella Blum, Naz Modirzadeh and Anthony Dworkin criticized the Article 51 argument, arguing Ukraine had not threatened or attacked another nation and that Donetsk and Luhansk are not recognized as separate states under international law and therefore cannot trigger collective self-defense.
•Genocide/humanitarian intervention: Scholars described Putin's allegations of genocide and comparison of Ukraine to a Nazi state as baseless. Experts also noted Russia's humanitarian justifications are widely perceived as a pretext and are unsubstantiated by evidence that Ukraine committed acts that could amount to genocide, and that whether international law even allows use of force to remedy genocide or human rights violations is heavily disputed.
•Comparisons to Western interventions: These comparisons have been dismissed as irrelevant because one illegal act does not make a different act legal. Professors noted "even if [they were] true, one illegal use of force does not justify another".
Due to the violation of the UN Charter, legal experts have also qualified the intervention as a crime of aggression under Article 8bis(1) of the Rome Statute.
The invasion is also said to have violated international agreements Russia is a 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.
Response at the United Nations
•In the UN Security Council, Russia vetoed a resolution calling for it to immediately cease its attack. China, India, and the United Arab Emirates abstained, while 11 members voted in favor.
•In the UN General Assembly, a resolution condemning the invasion was passed with 141 votes in favour, 5 against, and 35 abstentions. A later vote on 2 March 2022 was described as 141 against 5 demanding Russia withdraw and abide by international law, although General Assembly resolutions are not legally binding.
In summary, from Russia's perspective the operation was presented as justified on grounds of protecting populations in Donetsk/Luhansk, self-defense, denazification/demilitarization, and responding to NATO expansion. From the perspective of the UN General Assembly majority and most international law scholars, those justifications have been rejected and the invasion has been described as a violation of the UN Charter and other agreements.