Russia's Invasion of Ukraine
Learn about Russia's 2022 invasion of Ukraine — the largest land war in Europe since 1945 and a defining test of the post-Cold War international order.
Russia's full-scale invasion of Ukraine on February 24, 2022, was the largest military assault on a European nation since World War II and a watershed moment for the post-Cold War international order. Following Russia's 2014 annexation of Crimea and support for separatists in eastern Ukraine, the full invasion shocked a world that had believed large-scale conquest in Europe was consigned to history.
Russia expected a swift victory, but Ukraine's fierce resistance — led by President Volodymyr Zelensky and supported by Western arms and intelligence — stalled the invasion. What was predicted to take days turned into a grinding war of attrition with devastating consequences: tens of thousands of casualties on both sides, millions of Ukrainian refugees, destroyed cities, and documented war crimes including attacks on civilian infrastructure.
The invasion's geopolitical consequences have been profound. NATO expanded to include Finland and Sweden. Europe accelerated its shift away from Russian energy. The United States and allies imposed unprecedented sanctions on Russia. The conflict has raised fundamental questions about the durability of international law, the role of nuclear threats in great-power politics, and whether the world is entering a new era of imperial aggression. The war's outcome will shape international relations for decades.