There have always been tyrants and despots, but there is something fascinating about 20th century dictators. Mao Zedong, Pol Pot, Hitler, Saddam Hussein, Pinochet, Gaddafi, Khomenei, Idi Amin, all those guys.
A lot of them come from absolutely nowhere and can represent the greatest evil that is hidden within humanity. A lot of them have funny ideologies, some of them just fight for themselves, they really are a diverse group of the same rotten apples.
With the 20th century came more freedom for the average nobody and a greater ability for some random dude to acquire power over a country and carve his name into the book of history. We could see a LOT of these people pop up and many of them were alive at the same time as each other.
Surely there is still a lot more to the equation than that. How is it that so many tyrants managed to acquire power in the same century and what exactly made their rule different to dictators before the 20th century?
Generally speaking, the removal of power from monarchies played an important role in these tyrants coming to power. Later, the fall of imperialism also contributed to this. Both created power vacuums that allowed for power to be seized by those other than the upper/aristocratic classes. Most of those leaders came to power in revolution against entrenched regimes, being forces of great change. They lead mass movements in lands where the people were tired of their sociological, economic and political landscapes. Before the fall of the systems I mentioned, the voice of the people was pretty much irrelevant to those in power. Some of these tyrants capitalized on their anger and fervour. And unfortunately, people often forget that the masses are stupid, not really understanding what message they are supporting, but because they want change they throw their cards in with the lot that will bring about change. These tyrants used this negative passion to their benefit to amass a larger following. Media, and it’s evolution during this time also allowed for the messages of these men to be spread further, having their voice actually heard by their people (or actually being seen in person). Ex: Hitlers radio broadcasts and his arial campaign tours of Germany made him more accessible to the people. Both of those created a more personal feeling and relationship between people and these tyrants, something that wasn’t possible for monarchs or other leaders before this time. The fall of both monarchs and empires created many nationalist movements that were very aggressive and negative, something that these dictators preyed upon.
The 20th century was also an era of great democratically elected leaders, again thanks in part to the fall of both monarchies and empires. With the good comes bad as well.
In terms of what made their rule different from dictators of previous eras, industrialization, mechanization and the rapid evolution of communication of across their regimes played crucial parts in their ruling. Everything in life and ruling a populace became more efficient and happened faster.
My first time answering/posting here so my apologies if this answer is insufficient or inaccurate but this is what I’ve learned from my post secondary academic studies in history and politics, specifically fascism (hope that doesn’t sound pompous, just trying to show that I do have some knowledge in this area).