Is Russia's invasion of Ukraine justified?

I'll examine the legal claims around Russia's invasion of Ukraine and the international response.

Russia's full-scale invasion of Ukraine launched on February 24, 2022 has been widely assessed as illegal under international law, though Russia has offered several justifications for its actions.

1. What International Law Says

The central rule governing use of force is in the United Nations Charter:

> Article 2(4) of the United Nations Charter, which prohibits "the threat or use of force against the territorial integrity or political independence of any state."

Recognized as a peremptory norm-or jus cogens-this prohibition is non-derogable and universally binding.

Exceptions to this rule are extremely limited. Article 51 of the UN Charter permits self-defence only in response to an armed attack, and Chapter VII authorizes collective action through the UN Security Council to restore peace and security. Neither of these exceptions applied to Russia's invasion. Ukraine did not launch an armed attack against Russia, and the Security Council did not authorize any use of force.

Legal analysis concludes:

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

> Self-defense is the only justification for use of force against another country, according to international law. This condition is found in the U.N. Charter and is binding for all 193 U.N. member countries

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

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

The UN Secretary-General said Russia's invasion directly conflicts with the Charter, and 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 EU and UN statements have described it as:

> Russia’s illegal war of aggression blatantly breaches the core principles and rules of the UN Charter, including the sovereignty and territorial integrity of Ukraine

The UN General Assembly voted to condemn the invasion. The Security Council voted 11 to 1 to condemn Russia’s invasion, but the resolution was vetoed by Russia. The General Assembly voted 141 to five to censure Russia's aggression. Other General Assembly resolutions "overwhelmingly adopted a resolution demanding the Russian Federation immediately end its invasion of Ukraine and unconditionally withdraw all its military forces".

2. Russia's Stated Justifications

Russia invoked international law and the UN Charter to justify its invasion. In his February 2022 speech, President Vladimir Putin claimed:

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

•That also included claims that Ukraine was developing nuclear weapons

•That Russia was acting in self-defense, that its goal was the "demilitarization and denazification" of Ukraine

Other specific claims include:

•Protection of ethnic Russians and Russian-speaking populations under the Genocide Convention and a humanitarian intervention rationale

•Self-defence in light of NATO's eastward expansion, framed as crossing a "red line", with Russian officials framing NATO enlargement as the outcome of Western deception that allegedly violated informal assurances and ignored Russia's legitimate security interests

•An invitation to intervene after recognizing the self-declared Donetsk People's Republic (DPR) and Luhansk People's Republic (LPR) as independent and signing mutual assistance treaties

3. Why Those Justifications Are Rejected by Most Legal Authorities

•Genocide / humanitarian intervention: These allegations were widely rejected as untrue. No credible international organization or observer, including the United Nations or independent human rights monitors, found any evidence of genocide in Ukraine. When Ukraine brought a case to the International Court of Justice (ICJ) under the Genocide Convention, the Court issued provisional measures in March 2022, ordering Russia to halt its military operations and found no substantiation for Russia's genocide claims.

Even if the claim were true, it would not justify countrywide attacks. Humanitarian intervention is not a legally recognized exception to the prohibition on the use of force.

•Self-defence / NATO threat: Customary international law clarifies that the right to self-defence under Article 51 only arises in response to an actual or imminent armed attack. Vague threats or ideological adversaries do not fulfil the legal threshold. At the time of invasion, Ukraine had not attacked Russia. Analysts note NATO expansion did not violate any binding international agreement with Russia, and:

> Any Russian discomfort about NATO expansion cannot justify its brutal invasion of Ukraine

There was also no imminent prospect of Ukraine joining NATO at the time of the invasion.

•Invitation from DPR/LPR: The recognition of breakaway regions within another sovereign state does not establish a legal basis for intervention, particularly when such recognition occurs unilaterally and without broad international endorsement. The principle of territorial integrity remains paramount, and any "invitation" extended lacks legitimacy and cannot serve as a legal basis for military action.

4. Enforcement

While the Charter prohibits aggression, there is no standing international police force to enforce international law. The UN Security Council has authority to authorize use of force, but this is unrealistic because Russia holds veto power as a permanent member. The ICJ decides disputes, and the General Assembly resolutions condemning Russia are not legally binding but reflect consensus.

Citations (2)

1legalserviceindia.comCommercial content
The Legality of Russia's Invasion of Ukraine Under International Law
Backs: “What International Law Says. The central rule governing use of force is in the United Nations Charter: Article 2(4) of the United Nations Charter, which prohibits "the threat or use of force against the territorial integrity or political independence of any state."”
2tufts.eduAcademic
International law says Putin’s war against Ukraine is illegal. Does that matter? – Fletcher Russia and Eurasia Program
Backs: “Ukraine did not launch an armed attack against Russia, and the Security Council did not authorize any use of force. Legal analysis concludes: Under no scenario is Russia’s armed invasion of Ukraine legal under contemporary international law and norms”