Is Russia's invasion of Ukraine justified?

This is a contested question with competing legal and political arguments — I'll survey the international law, UN findings, and Russia's stated rationale.

Russia's 2022 invasion of Ukraine is considered justified by Russia and not justified by Ukraine, the majority of UN member states, and most international legal experts. The assessment depends on which legal and political framework is applied.

What Russia claims

On 23-24 February 2022, President Vladimir Putin announced a "special military operation" in Ukraine. He claimed that:

In public speeches and state media, Moscow also framed the operation as a response to alleged threats posed by NATO expansion — rhetoric used to justify the invasion to domestic and international audiences

Putin stated that Ukraine joining NATO posed a security threat and preventing it was among his strategic objectives.

Scholars described Putin's allegations of genocide and comparison of Ukraine to a Nazi state as baseless.

What international law says

Since the beginning, the Russian invasion of Ukraine has been described as violating international law (including the Charter of the United Nations). Amnesty International said Russia’s invasion of Ukraine is a clear violation of the United Nations Charter and an act of aggression that is a crime under international law.

The key legal provisions are:

Many experts on international law and foreign affairs have opined that the Russian invasion violated these principles, namely Article 2(4)'s prohibition on the "use of force" and have generally rejected the Russian government's official legal justifications.

Specific rejections of Russian legal arguments:

1. Collective self-defense under Article 51: Russia has argued that its use of force is lawful under Article 51 which preserves rights to defend themselves against "an armed attack" and to engage in "collective self-defense," specifically to defend the Donetsk and Luhansk People's Republics. Experts criticized this argument, noting Russia cannot rely on self-defense because Ukraine has not threatened or attacked any other nation, and even if it had, these regions are not recognized as separate states under international law.

2. Humanitarian intervention / genocide: Experts have rejected Russia's argument that its invasion is justified on humanitarian grounds to protect Russian-speakers in the Donbas. Russia's humanitarian justifications are widely perceived as a pretext, and are unsubstantiated by any evidence that Ukraine has committed acts that could amount to genocide.

3. Comparisons to Western interventions: Russia has also tried to justify its invasion by comparing its actions to interventions by the United States and its allies during conflicts such as the Kosovo War, the Iraq War, and Libya. These comparisons have been dismissed as irrelevant because one illegal act does not make a different act legal, with scholars noting "even if [they were] true, one illegal use of force does not justify another".

The invasion was also said to violate other agreements Russia is party to, including the 1975 Helsinki Final Act and the 1994 Budapest Memorandum, in which Russia agreed "to respect the independence and sovereignty and the existing borders of Ukraine".

Response at the United Nations

In short, under the UN Charter framework as interpreted by most states and international courts and scholars, the invasion is not considered legally justified because there was no armed attack on Russia, no Security Council authorization, and the humanitarian claims lack evidence and do not create a legal basis for the use of force. Russia maintains that its security concerns and protection claims do provide justification.