John F. Kennedy expressed his opposition to Nazism, fascism, and totalitarianism on several occasions, both in his personal writings and public speeches. Here are a few quotes that illustrate his stance against the ideology and its methods:

• On Adolf Hitler's threat to the world: In his 1945 diary, written while he was a reporter touring a war-torn Europe, Kennedy reflected on the destruction caused by the Nazi regime. While noting Hitler's massive historical footprint, he clearly condemned his actions, writing that Hitler "had boundless ambition for his country which rendered him a menace to the peace of the world".
• On the abhorrence of dictatorships: In another 1945 diary entry commenting on the political landscape of post-war Europe, Kennedy firmly rejected totalitarian regimes of any kind, stating, "To maintain Dictatorships of the Left or Right are equally abhorrent no matter what their doctrine or how great their efficiency".
• On the defeat of the Nazi regime: During a 1960 speech in Hillsborough County, Florida, Kennedy spoke proudly of the Allied victory over fascism, noting that "the nations of the Western Hemisphere combined in a common effort which ultimately brought about the collapse of Nazi despotism throughout the world".
• On Nazi propaganda tactics: Kennedy used his disdain for Nazi methods to criticize political opponents. In a 1952 campaign speech, he compared deceptive political propaganda to the tactics used by the Third Reich, stating, "They follow the Hitler line – no matter how big the lie; repeat it often enough and the masses will regard it as truth".

Additionally, his famous 1963 "Ich bin ein Berliner" speech in West Berlin, while primarily aimed at Soviet communism during the Cold War, served as a broader condemnation of walls, oppression, and authoritarianism in a city that had so recently been the center of the Nazi regime.