Governments in the Middle Ages in Europe expressly divided power among groups of people that were called "Estates". For example, in Britain, power was divided among the Crown, the Lords and the Common people. In Continental Europe, there was the Crown, the Church, the Nobles and the Peasants. Some nations had other Estates, such as the Merchants in cities and the Jews. Often justice was meted out differently for persons in different estates. Certain powers, such as taxation or declaration of war, were reserved for certain estates.
What are the "Estates" in modern America? I'll generalize a bit here, but I think several Estates are clearly distinguishable.
The Crown Estate: That's Washington DC. Here I'm expanding the Crown Estate to include the entire Court of the Crown - "DC". I'm including the Executive branch high officials, all Congress and the Supreme Court and other major or special courts in DC. Besides having real executive, legislative and judicial decision power, they get many special privileges depending on rank: tax breaks, parking spaces, have taxes to pay for all sorts of perks, exemptions from waiting in many lines, and of course have real power to threaten anyone who doesn't give them what they wish. Most have de facto lifetime tenure, but the judges had de jure lifetime tenure. So all are unaccountable for most consequences of their decisions.
The Nobility: Easy again, they are the "Rich and Powerful". They also have many special privileges, tax breaks and have special access to the Crown, either directly or by special agents called lobbyists. And they get the first vote for selecting a President. No person can make a successful run for that office with securing many votes of the Nobility. Through the courts they can force almost any person to submit to their will or suffer ruin.
The Church: Again, easy. These are two groups - the Press and the Environmentalists now. Their power and privilege is legally guaranteed in many laws that give them special power over people and their actions and property of almost anyone. The Press can smear anyone with near impunity and can similarly lie endlessly to pressure the Crown; the Environmentalists can bind someone's property and actions tightly with lawsuits under increasingly broad laws. The Church in the Middle Ages claimed power over souls, analogous the the power of the Press over one's reputation. And the Church also had power over a huge range of human behavior and lands, much like the modern Environmentalists.
The Merchants and Guilds: Here I put several groups who act mostly separately, but sometimes coordinate. Major corporations, the business lobby, unions, the trial lawyers, and the activist groups. All have special tax breaks and powers, either de facto or de jure.
The Peasants: That's the rest of us. We have no special tax breaks, no special privileges, and little power most of the time. Only when strongly motivated by some event or issue can the Peasants move the government. At other times the Peasants are a disorganized rabble easily manipulated with propaganda or by demagogues.
This thinking is a work in progress, but I'm going to use this paradigm in the future to analyze modern American politics.