Key World War II Lessons to Prevent Another Global Conflict

This Thursday marks the 80th anniversary of the conclusion of World War II in Europe, a date of profound significance for nations deeply affected by the conflict. We honor the memory of our parents, grandparents, and relatives who valiantly defended freedom against the tyrannies of the 20th century. We solemnly remember the millions who lost their lives, including the six million Jews exterminated during the Holocaust, as well as countless victims of Soviet repression that persisted behind the Iron Curtain even as Europe sought reunification and recovery.

Commemoration serves a vital purpose: to extract essential lessons from history and ensure that past errors are not repeated. We present five key lessons from World War II that are crucial to understanding how to establish and sustain a just and lasting peace and security in Europe today, especially as these values face renewed challenges.

Much like the great wars before it, Russia’s full-scale invasion of Ukraine on February 24, 2022, has marked a profound turning point in the 21st century. Despite facing overwhelming adversity, Ukraine has successfully pushed back the invasion and regained control over more than half of the occupied regions. However, even after sustaining immense casualties—exceeding 950,000 Russian soldiers killed and wounded—the aggressor has not relinquished its expansionist ambitions.

The Russian leadership aims to leverage the current geopolitical landscape to secure concessions from Ukraine and its allies. Moreover, Moscow has increasingly allied with other authoritarian regimes such as Iran and North Korea, posing security threats not only to Europe but also to the Indo-Pacific and Middle Eastern regions.

Learning from history is imperative as Ukraine, the European Union, and the United States strive to achieve peace. Russia’s aggression has disrupted the post-World War II security framework and the international order founded on the United Nations Charter and the Helsinki Accords. The resolution of this conflict will shape the foundation of a new security architecture. The lessons from World War II outlined here must guide efforts to forge enduring peace in Ukraine rather than merely postponing the prospect of another catastrophic global war.

One critical lesson is that appeasing an aggressor only fuels further aggression rather than securing peace. Making concessions on illegal territorial claims is a grave error. The 1938 partition of Czechoslovakia emboldened Nazi Germany, ultimately triggering a global conflict. Applying this lesson today, Ukraine will never accept any legitimization of Russia’s occupation and annexation of its territories. Respect for sovereignty and territorial integrity remains a cornerstone of international law. Sustainable peace and security cannot come at the expense of Ukraine’s independence, sovereignty, or territorial unity.