One of the human race’s biggest problems has been that people who occupy positions of power are often incapable of using power in a responsible way. In the past, this was mostly due to hereditary systems which assigned power to kings and lords and others, who often didn’t have the intellectual or moral capacity to use their power well. But in more recent times, it seems as though power attracts ruthless and narcissistic people with a severe lack of empathy and conscience.
In psychology, there is a concept of a “dark triad” of malevolent personality traits: psychopathy, narcissism and Machiavellianism. These traits are studied together because they almost always overlap and combine. If a person has psychopathic traits, then they tend to have narcissistic and Machiavellian traits too.