Is Russia's invasion of Ukraine justified?

The question of justification is contested — I'll gather the legal, historical, and international perspectives to give you a full picture.

Russia's 24 February 2022 full-scale invasion of Ukraine is widely considered illegal and unjustified under contemporary international law, though Russia has offered its own legal and political justifications which have been rejected by most states and international bodies.

1. What international law says

The core rule is in the U.N. Charter:

> "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:

> Russia's invasion of Ukraine violates Article 2(4) of the UN Charter, a central tenet of the charter that requires UN member states to refrain from the "use of force against the territorial integrity or political independence of any state."

Under international law:

> Self-defense is the only justification for use of force against another country, according to international law.

More specifically:

> The charter's only clear exception to prohibiting the use of force is self-defense, "if an armed attack occurs" against a country.

2. Russia's stated justifications

In his 24 February 2022 address announcing a "special military operation," President Vladimir Putin:

> Putin claimed that Ukraine had been committing genocide against Russian speakers in the region; that Ukraine's government were neo-Nazis under Western control; that Ukraine was developing nuclear weapons; and that NATO was building up military infrastructure in Ukraine, threatening Russia.

The full speech also framed the action as:

> Russia was launching a "special military operation" to defend the Russian-speaking territories in eastern Ukraine—the Donetsk People's Republic and Luhansk People's Republic—under Article 51 of the United Nations Charter

And invoked:

> in accordance with Article 51 of Part 7 of the UN Charter, with the sanction of the Federation Council of Russia and in pursuance of the treaties of friendship and mutual assistance ratified by the Federal Assembly on 22 February of this year with the Donetsk People's Republic and the Luhansk People's Republic, I have decided to conduct a special military operation.

Putin also cited NATO expansion, saying NATO expansion to the east and military development in Ukraine was "unacceptable" and that an "anti-Russia" was being created on territories historically Russia'sand.

3. Why those justifications are rejected by most legal experts and international bodies

a) No armed attack by Ukraine:

> Nothing that Ukraine has done to date could be construed as an "armed attack" on Russia and justify any Russian claim to self-defense.

And the Council on Foreign Relations analysis notes:

> Ukraine did not commit or threaten to commit an armed attack against Russia or any other UN member state. Even if Russia could show that Ukraine had committed or planned to commit attacks on Russians in the Ukrainian regions of Donetsk and Luhansk, Article 51 would not permit an action in collective self-defense, because Donetsk and Luhansk are not UN member states.

Legal scholars view Putin's Article 51 claim as incorrect because:

> Article 51 of the UN Charter allowed one UN member state to give military aid to another member state; but the DPR and LPR were not UN member states and were only recognized as independent by Russia.

b) Genocide claim not supported:

> Putin's accusation that Ukraine was committing genocide in the Donbas have been widely rejected as baseless by other countries and international organizations

> Ukraine brought a case before the International Court of Justice (ICJ) to challenge Russia's claim. The ICJ said it had not seen any evidence of genocide committed by Ukraine.

And:

> In March 2022, the Court explicitly rejected Russian claims of genocide

In legal terms:

> There is no evidence that Ukraine engaged in any of the defined actions and certainly no evidence of an intent to destroy in whole or in part any group in eastern Ukraine. Even if the Ukrainian government had committed human rights abuses... neither the Genocide Convention nor the UN Charter authorizes convention parties or UN member states to use force to remedy acts of genocide

Even if humanitarian concerns existed:

> Intervening for humanitarian reasons... has not yet been widely accepted, unless the U.N. Security Council authorizes the intervention.

> Countries cannot avoid their international obligations by pretending their actions are peacekeeping missions, as Putin has said.

And:

> Under no scenario is Russia's armed invasion of Ukraine legal under contemporary international law and norms.

4. International community's position

> the Russian Federation committed an aggression against Ukraine in violation of Article 2(4) of the United Nations Charter.

On 2 March 2022 it adopted a resolution:

> demanding the Russian Federation immediately end its invasion of Ukraine and unconditionally withdraw all its military forces

The vote was 141 for, 5 against, 35 abstaining, and later resolutions described the action as:

> Russian aggression against Ukraine is a grave violation of the United Nations Charter

> The EU condemns in the strongest possible terms Russia's unprovoked and unjustified military aggression against Ukraine ... which grossly violates international law, the UN Charter

5. Summary

Whether one considers the war "justified" therefore depends on whether one accepts Russia's factual claims and legal interpretation of self-defense, or the prevailing international legal interpretation which rejects them.