In “The semantics of twenty-first century socialism and the Venezuelan political system,” José Javier Blanco Rivero writes
The French philosopher [Claude Lefort] explains that in the Middle Ages the king represented the unity of the political community, but as the age of revolutions toppled monarchies a new form of government was devised where anyone could play the role of ruler, and so no one was ruler but the people themselves. As a consequence, there is no possible way to represent the unity of the political community. This is why, for Lefort, democracy is an empty space, a vacuum left by previous self-descriptions of politics, which somehow produces social anxiety in moments of deep crisis. Thus, the absent king, representing the unity of the system within the system, is replaced by the Führer, Il Duce, or other great leader who becomes one with the people. Such is, argues Lefort, the ideological outset of totalitarianism.
The medieval sovereign was supposed to represent the unity of a society within that society, or realm. The sovereign, as a transcendent power, would govern the subjects. But under democracy, the people are supposed to govern themselves; however, complete democracy, where the people would have to vote on every single issue, is a practical impossibility, and the solution is representational government, or a republic.
Another practical reason for the impossibility of true self-government is that people share resources. We share roads, for instance; each person does not construct and maintain their own road to town. We share railroads and air-travel routes. Beginning in the early modern era, people began to share postal systems. We share the expense of common defense, including border maintenance and protection or trade routes, including shipping channels. Piracy was a serious problem in the 17th-18th centuries.
But when the people come to believe or realize that their political representatives are not actually representing their interests, faith in representative government collapses. And demagogues like Trump fuel the distrust of the corrupt, “rigged” system. He portrays himself as a “strong man” who can solve all social problems. The absent king, representing the unity of the system within the system, returns.
But governments fall when they lose legitimacy. The early modern monarchs could not handle the social complexity of the time. And there’s no way a strong man can manage 21st century complexity.