The concept of "totalitarianism" was popularized by Hannah Arendt in her book The Origins of Totalitarianism, published in 1951 right at the start of the heated phase of the Cold War.

Inside it, you can see her contradict herself within the bounds of her own concepts, but the main issue is: it attempted to create a false parallel between what she calls "Stalinism" (supposedly the ideology of the Soviet Union at the time) and Nazism, as if they're two sides of the same coin. When, of course, they aren't. This is what we call "making up a concept, pointing to two things in the world, and saying those are the same."

The book also says that totalitarianism is novel in that it attempts to terrorise whole populations instead of only political adversaries, so as to whip the people into shape, when in material terms, we know that isn't what happened in the Soviet Union, and neither in Nazi Germany honestly.

Supposedly, totalitarian movements would attempt to control every single aspect of the life of their subject, and this would be why Hitler and Stalin were totalitarians and Mussolini isn't, because Mussolini would 'just be an autocrat' who wants to subjugate their political opposition.

Many people would mention that she forgets a spooky thing called slavery, that did the same thing. Capitalism could be argued to do it too, colonialism also, etc.

All that aside, a lot of people criticised her for just not understanding certain events correctly. For instance, she mentions that the Nazis weren't really interested in murdering all Jews; instead, those were simply a convenient proxy— a 2-minute hate, if you will— to whip up your population. Therefore it'd be comparable to any famine from the USSR, since intent would be similar, according to her. This fundamentally misunderstands the Nazi project in a futile attempt to draw a line between two different things for political purposes, and ignores historical documentation of intent like the Wannsee conference and Generalplan Ost.

Bottom line: Hannah Arendt created Cold War propaganda to try and equate the old enemy (Nazi Germany) with the new one that was finding itself in the Korean War (Soviet Union). Liberals gobbled this up because they're scared of big words like "authoritarianism", and therefore she had a ton of success. Her theories ignore the political violence of the state and of capitalism because, in her liberal mindset, these weren't actual violence, but instead just the way the world works. This flies in the face of everything the Third World ever tries to accomplish, because our revolutionary violence wouldn't be justified.

It's almost like a "big-tent" propaganda, you can take a million conclusions out of this, and it's been deeply influential.

As a final note, Hannah Arendt was extremely racist in defense of colonialism.

credit to u/Logan_Maddox