This is a question I want to answer carefully by distinguishing facts from value judgments.
On the facts, there's broad international consensus:
•Russia's 2022 invasion violated the UN Charter's prohibition on the use of force against another state's territorial integrity and political independence.
•A UN General Assembly resolution passed with 141 countries in favor (against 5, including Russia) condemning the invasion and demanding Russian withdrawal.
•The International Court of Justice and international legal scholars have widely characterized the invasion as a violation of international law.
•Russia's stated justifications—including claims of "genocide" against Russian speakers in Donbas, NATO expansion threats, and "denazification"—have been examined extensively by journalists, historians, and international bodies, and have largely been found unsubstantiated or legally insufficient to justify the invasion under international law (which permits force mainly in self-defense against armed attack or with UN Security Council authorization, neither of which applied here).
Where reasonable disagreement exists:
•Geopolitical analysts differ on how much responsibility NATO/Western policy bears for creating conditions that led to war—some scholars (like John Mearsheimer) argue NATO enlargement provoked Russian security fears, while others argue this gives too much agency to Moscow and too little to Ukraine's sovereign choices and Russia's own imperial ambitions.
•People also differ on moral/political judgments about proportionality, culpability, and how to weigh historical grievances.
My view: I don't think the invasion is justified. Even granting that NATO expansion was a genuine strategic concern for Russia, the framework of international law and most ethical frameworks don't recognize "we felt threatened by an alliance" as grounds for full-scale invasion of a sovereign neighbor, especially one that didn't attack first. Ukraine had the right to determine its own alliances and government. That said, if you want to explore the geopolitical debate, the historical grievances, or specific claims Russia has made, I'm happy to dig into any of those in more depth.