One of these days I’m going to have to write a whole entry by itself on the classical doctrine of the “mixed constitution” and its role in Medieval political thought, but for now I just ran across this interesting section from Aquinas where he states that the mixed constitution is the exact form of constitution established by the Divine Law (i.e., Scripture):
…And so the best constitution for a city or kingdom is one in which one person rules in accordance with virtue, and under him there are others who govern in accordance with virtue, and all have some part in government because they are all eligible to govern and those who govern are chosen by all. This is the best form of polity since it is a judicious combination of kingship – rule by one man, aristocracy – rule by many in accordance with virtue, and democracy – i.e., popular rule in that the rulers can be chosen from the people and the people have the right to choose their rulers.
This was the form of government established by the divine law. Moses and his successors governed the people as sole rulers over all so that there was a kind of kingship. Seventy-two elders were chosen in accordance with their virtue, as Deuteronomy says, “I took out of your tribes wise and noble men and made them rulers” and this was the aristocratic aspect. But it was democratic in that they were elected from all the people, since Exodus says, “Provide wise men from all the people” and also because the people chose them, as Deuteronomy says, “Give me wise men from among you” etc. Therefore it is clear that the constitution that the [Old] Law established was the best.:”(Cited from the Summa Theologiae Q. 105, as trans. and ed. by Paul E. Sigmund, St. Thomas Aquinas on Politics and Ethics [New York and London: W.W. Norton and Co., 1988], pg. 59.)”:
The concept of the “mixed constitution” has a lot to do with classical pagan and Medieval Christian attempts to find the best form of social organization to help man achieve his natural end, and also to restrain various forms of excess to which government is prone. If I have time later, I’ll outline Aquinas’ understanding of kingship vs. tyranny and try to apply his remarks about the “mixed constitution” to that very important issue.