People attracted to political office, especially higher office, are generally not of sufficient character to discharge the duties of said office. This has been true forever. The ancient Greek historians talk about this constantly, hubris, memesis, human nature, etc. The central Roman political issue was the collapse of virtue.
The same cause, that is, human nature, destroys democracy when the people come to refuse to distinguish between good and evil. That time always comes. Fantasy replaces reality and lust replaces responsibility.
For “memesis” read “nemesis”, of course.