If someone gives you something or helps you , it is a natural human instinct to feel obligated to them. Psychopaths consist of roughly 4% of the population, but this can vary its time and place. They do not have this instinct, but they have learnt  how to exploit it by lying to, and cheating, non- psychopaths.  

“Government” is essentially psychopaths controlling non-psychopaths. 
This is why there is no “correct” form of government/political system. Politics is a vicious game played by psychopaths with each other.

Societies  change/collapse when non-psychopaths become aware of their exploitation by some means. Politicians try to slow this down by censorship and even imprisoning people who facilitate this awareness. i.e “Hate speech “

  Political theories  are based on the idea that people are NOT divided into psychopaths and non-psychopaths.  Hence :  “Equity” “Equal rights” “Human rights”  “each according to his ability “ 
“Societal values” .
It is laughable that Political Science does not discuss psychopathy.

In the past people lived in small groups/villages. By means of gossip, it was very difficult for psychopaths to operate without being discovered. When they were discovered they were made to leave the group, which effectively meant death.