Is Russia's invasion of Ukraine justified?

This is a question where I can offer factual context and different perspectives, but not a definitive personal verdict—it's a deeply contested political and legal question, and I want to be upfront that reasonable people (and importantly, legal bodies) have weighed in with strong conclusions on one side.

The legal/international consensus view:

Under international law, the case against the invasion's legality is quite clear-cut. The UN Charter prohibits the use of force against the territorial integrity of another state except in self-defense or with UN Security Council authorization. Russia had neither. The UN General Assembly voted overwhelmingly (141-5) in March 2022 to condemn the invasion as a violation of Ukraine's sovereignty. The International Court of Justice and International Criminal Court have also taken actions consistent with viewing the invasion as unlawful, including an ICC arrest warrant for Putin.

Russia's stated justifications and their reception:

Russia has offered several justifications: protecting Russian-speaking populations in Donbas, preventing NATO expansion, "denazifying" Ukraine, and claims of historical unity between the two nations. These arguments have been widely rejected by the international community, most Western and international legal scholars, and independent human rights organizations. Ukraine is a sovereign, internationally recognized state, and none of these justifications meet the recognized legal thresholds for self-defense under the UN Charter.

Where genuine debate exists:

Some analysts and political theorists (a minority view, particularly among certain realist international relations scholars) argue NATO expansion created legitimate security concerns for Russia that contributed to the conflict's origins—this is a debate about causes and context, not a legal justification for invasion. Most scholars who make this argument still don't claim the invasion itself was lawful or justified; they're making a separate point about how the conflict could have been avoided through diplomacy.

My take:

I'll be direct: based on the near-universal legal consensus, the scale of civilian harm, and the lack of a credible self-defense claim, I don't think the invasion is justified. That's a conclusion I hold with reasonable confidence given the weight of international law and evidence, though I recognize this involves value judgments about sovereignty and security that not everyone weighs identically.

If you want, I can dig deeper into specific aspects—the NATO expansion debate, the legal case in more detail, or how different countries/regions have responded.