So much for preliminary stuff. Now on to the main body. Aristotle's Politics is probably best known for dividing governments into the many, the few, and the one. He also divides them into good and bad. In Aristotle's view, government is good when its rulers -- whether many, few, or one -- think of the public good and corrupt when its rules -- many, few or one -- think only of their own private good. By this standard, the great majority of governments, particularly of the many, have been bad. Indeed, Aristotle has misgivings about whether good government of the many is even possible.
He calls government of the one kingship when it is good and tyranny when it is bad. (Both fit under the category of monarchy, "mon" meaning "one.") Good government of the few is aristocracy, or government of the best. Bad government of the few is oligarchy, or government of the rich. (Or, as we call it in modern pseudo-Greek, plutocracy). Bad government of the many is democracy or rule of the demos -- the lower classes. Good government of the many is "politeia," generally translated as constitution or polity and meaning, so far as I can tell, government of the whole, or government of the entire body politic. Elsewhere he uses "politeia" to mean both the structure of government and the larger structure of the body politic and the whole society. As such, it is often translated as "constitution," although so far as I can tell, "polity" probably works better. And when used to mean good government of the many -- well, I am not sure there is any equivalent English term. I think he means government of the whole body politic, which is a rather clumsy phrase, so I will stick to politeia.
Aristotle differs from Plato in distinguishing between the best government a philosopher can imagine and the best government you are likely to get in the real world. Plato, when asked whether his ideal government was actually achievable, took refuge in the allegory of the cave in which he explains that this world we live in is not real, and that the ideal world is a higher reality, meaning that the best government a philosopher can imagine is more "real" than anything in the real world. Another famous Greek had the name for that -- "sour grapes." Aristotle, by contrast, was realistic enough to recognize that when a society entrusts its well-being to the virtue of its rulers (whether many, few, or one) it rests on a frail foundation. Kings degenerate into tyrants, rule of the best degenerate into rule of the rich, and rule of the whole degenerates into rule of the mob. Although Aristotle distinguishes between different kinds of kingship, tyranny, aristocracy, oligarchy, politeia, and democracy, running through his types of bad government is a crucial distinction. Government can be "corrupt" in the sense of self-seeking but still respect the rule of law. Lawless government -- whether of the many, few, or one -- is always the worst. Keeping government from being corrupt (self-seeking) depends on the virtue of its rulers. Maintaining the rule of law depends on institutions. So Aristotle wrote at length about institutions.
His concept of a king deserves some attention because it is different from most people's concept of a king today. Although we recognize absolute, limited, and constitutional monarchies, we tend to assume that a king is necessarily hereditary and for life. But Aristotle discussed hereditary absolute monarchies (for life), elective absolute monarchies (for life), temporary monarchies for an emergency, and limited monarchies for life, like the Spartan kings (Sparta had two kings at once, who were hereditary and for life, but whose power was limited to military command). He said that the distinction between a king and a tyrant was that a king ruled willing subjects by law and a tyrant ruled unwilling subjects by force. He shows a distinct distaste for life-long absolute monarchs (hereditary or elective), saying that Greeks would never submit to such a servile arrangement, but that non-Greeks seem to accept it. An odd comment for Alexander the Great's tutor, but no matter.
He describes at length the institutions of government by the many and few with an emphasis on their bad forms. The details need not interest us so much as the generalities. Government of the few is bad, he says, when the rich rule because they are rich. Government of the many is bad when the poor rule because they are poor.* The idea of rule by the poor or lower classes may seem fantastic to us, but Athens of Aristotle's day (and perhaps other democratic city-states as well) was as close to such a state of affairs as one could plausibly achieve.
Then as now, the marks of first-class citizenship are and were the right to vote, to hold office, to sit on juries and to serve in the military. The problem is that, then as now, those rights and privileges of citizenship were also burdens. The right to vote means taking the trouble to be informed to some degree, and to care. It was more burdensome in ancient Greece because voting did not just mean marking a slip of paper, but attending the Assembly and participating in (or at least listening to) debates. The ratio of officer holders to citizens in those days also made the chances of any politically active citizen actually holding office much higher in those days than now. The burdens of jury service and military service go without saying. There were two ways of dealing with this problem, one oligarchic and one democratic. Aristotle explains how a formally democratic system can become a secret oligarchy by penalizing non-attendance in the Assembly, or jury-courts, or military training with a fine, and then allow hardship exemptions. All but the richest citizens will end up claiming a hardship exemption and only the rich will exercise real power. Aristotle saw this as an injustice. By contrast, a city that takes democracy seriously (as Athens did) can pay its citizens to take part, but make the amount meager enough only to attract the poor.** The poor become a professional body of jurors and legislators, while the upper classes begin to look down on governing as poor man's work. This, too, Aristotle saw as injustice.
In looking for institutions to avoid injustice, Aristotle urged his government to seek the golden mean. Narrow and tight oligarchies were a threat to the rule of law because the rich will seize power and completely corrupt institutions. A relatively broad and loose oligarchy is to be preferred. In democracy, Aristotle preferred a mostly passive population whose participation was minimal. Let the poor exercise actual government, and it will degenerate into mob rule. He recommends a large middle class to minimize the numbers of rich and poor.
But above all, he talks about how to maintain a well-balanced politeia combining democratic and oligarchic features. In other words, even if both the many and the few become corrupt, well-balanced institutions can minimize the harm done. He is somewhat contradictory on how this is to be done. At one point, he suggests allowing all to vote without property restriction, but make all offices elective (as opposed to chosen by lot) and with property restriction. Another time, he proposes paying poor citizens to participate and fining rich citizens who do not, to ensure participation by all. Yet another, he proposed matching equal numbers of the upper and lower classes in each jury. But another time, he proposes limiting the vote to soldiers but not sailors, i.e., men who can afford gear (soldiers) as opposed to men who cannot (sailors). The poor will not mind being excluded, he says, so long as they are not mistreated. But then again, he acknowledged, without political power they will be at the mercy of the citizenry, whose virtue cannot always be counted on. Finally, he attempts some elaborate system of weighing votes by wealth so that the numeric majority and the majority of wealth will have equal power and each be able to keep the other from prevailing. In case of a tie, wealth should prevail. If someone had suggested a bicameral assembly, with one house for the rich and one for the poor and all legislation having to pass both, presumably he would have approved. Or maybe not. In one of his final chapters Aristotle appears to limit citizenship to men of sufficient wealth to have the leisure not to work and be able to devote themselves full-time to government. Sounds like an oligarchy to me.
I should make one final note. Aristotle agrees that democracy is the form of government most conducive to freedom. Indeed, he says that liberty is the first principle of democracy. Plato, in his Republic, appears to agree. But that does not mean that either man favored democracy. Rather, both believed that, while too little freedom meant oppression, too much meant chaos. The object of government was not just to protect society's freedom, but its overall well-being or eudaimonia. Freedom was an aspect of eudaimonia, but only a part of it. Or, put differently, you could get too much freedom, but never too much eudaimonia.
*He briefly toys with the idea that hypothetically there could be a society with many rich and few poor,but dismisses it as mostly an episode of Games Philosophers Play.
**As a practical matter, the city would not be able to afford to pay more than a pittance anyhow.