A quick lesson on despotism and authoritarianism from a historian's POV
These two ideas are two of the most successful theories and practices in the history of civilization.
All you need is someone with no remorse (psychopath), no empathy (narcissist), ego driven (megalomaniacal), who only sees two ways (binary) and sees enemies everywhere (paranoia). The authoritarian despot must also know how to charm and appeal to people (manipulative) and create a world where all that matters is the despot (cult of personality). Finally, the despot must have the ability to justify everything and regret nothing (Machiavellian), as well as convince the people that they are safer with the despot (gaslighting).
Creating this world is extremely easy. Maintaining it is also extreme easy. All one has to do is:
1) Appeal to nationalism and xenophobia
2) Scapegoat a popular boogeyman
3) Discredit than eliminate the opposition
4) Create an apparatus that is loyal to the despot more than the country
5) Terrify the people into submission
6) Give the spoils to your most loyal supporters
Every despot in history has done this. Murdering unarmed people is easy. Look at Papa Doc, Idi Amin, the Kims, Mao, Pol Pot, Rhee, Pinochet, and the others (I am leaving the big names out because it is too easy to point them).
Controlling a population is easy when they are defenseless.
It's just when they are trying to kill people that shoot back is where they begin to have their problems. And that usually leads to their downfall.