The invasion raises contested legal and political questions — I'll gather the competing claims to give you a balanced overview.
Russia's 2022 full-scale invasion of Ukraine is viewed differently depending on the framework used to assess justification. The main arguments and counter-arguments are:
1. Russia's stated justifications
In announcing a "special military operation" on 24 February 2022, President Vladimir Putin said its aims were to protect people in the Donbas from what he called genocide and to "demilitarise and denazify" Ukraine.
Russian officials and state media have elaborated three primary justifications: Nato expansion, "denazification," and demilitarisation.
Specific claims include:
•Security and NATO expansion: Putin has contended that Nato's true purpose is not to uphold democracy but to restrict Russian influence, thereby forcing Russia into a corner. A related claim is that Russia's security interests justify the war, and that verbal assurances of NATO's non-expansion given to the USSR in the 1990s were broken.
•Protection of Russian speakers: Russia claims a right to use force to protect people beyond its borders who speak its language or share its culture. The argument was that the Ukrainian government posed a threat to ethnic Russians and Russian-speaking populations in eastern Ukraine, harbouring "dangerous Nazi elements intent on oppressing Russian-speaking citizens".
•Legal justifications: Russia's only official legal justification is contained in Putin's speech on the day of the invasion. It argues that the "operation" is an exercise of Russia's right to self-defence under Article 51 of the UN Charter. Other legal arguments evaluated by scholars include claims of individual self-defence, collective self-defence on behalf of the self-proclaimed entities of Donetsk and Luhansk, humanitarian intervention, protection of nationals abroad, and allegations of genocide in eastern Ukraine. It also framed the action as part of a struggle for a "fairer" international order.
2. Ukrainian, Western and international legal assessments
•UN Charter: The 1945 UN Charter sets out the conditions under which UN member states may legally resort to war. One rule that became binding in 1945 is that states must not use military force against other states except defensively or if the UN Security Council authorises it.
•Article 2(4): The full-scale invasion is widely described as a direct violation of Article 2(4), which prohibits the use of force against the territorial integrity or political independence of any state. The same article is quoted as requiring all UN members to "refrain in their international relations from the threat or use of force against the territorial integrity or political independence of any state".
•Illegality under international law: Legal analyses conclude Russia's attack constitutes an international use of force prohibited by Article 2(4) and does not fall within the exception of self-defense under Article 51 and is therefore unlawful. Other assessments state the invasion violated the prohibition of force in the Charter and the peremptory norm prohibiting aggression.
•UN General Assembly response: On 2 March 2022 the UN General Assembly voted overwhelmingly to condemn Russia's invasion. 141 member states voted in favour of the resolution, with just four states joining Russia in opposing it: Belarus, Eritrea, Syria and North Korea. Another count describes the vote as 141-5 with 35 abstentions, the five against being Russia, Belarus, Syria, North Korea and Eritrea. A separate analysis notes the General Assembly, by 141 votes, deplored aggression by the Russian Federation against Ukraine in violation of Article 2(4).
•Rejection of Russian claims: Ukraine and Western governments rejected the claims of genocide and denazification as baseless. A UK statement to the OSCE argued that Russia claims security interests justify its war, but that security is indivisible and no state should strengthen its security at the expense of others.
In summary, from Russia's perspective the invasion is presented as justified self-defence, protection of co-ethnics, and a response to NATO expansion and historical injustices. From the perspective of Ukraine, most Western states, and the majority of UN member states and international lawyers, it is considered a violation of the UN Charter's ban on the use of force and an illegal war of aggression.