Eighty years ago, World War II broke out in Europe. Remembering this anniversary provides an opportunity to reflect on what we might learn from studying the history of that hideous era. Of the many accounts on the war’s origins, Winston Churchill offered one of the most insightful interpretations about how a return of great-power competition shattered Europe’s peace. His condemnation of Great Britain’s leaders for seeking to appease the Nazi dictator offers a sobering lesson in the failure of the world’s democracies to arm themselves and band together to preserve the peace. Churchill lamented that democracy had been weighed in the balance and found wanting. His lamentation still serves as a warning against the folly of military weakness and foreign policy isolation.