In the Summa Theologica first part of the second part, question 105 (ST, I-II, 105.1) Thomas Aquinas discusses what he considers to be the best form of government. “For this is the best form of polity, being partly kingdom, since there is one at the head of all; partly aristocracy, in so far as a number of persons are set in authority; partly democracy, i.e. government by the people, in so far as the rulers can be chosen from the people, and the people have the right to choose their rulers.
Such was the form of government established by the Divine Law. For Moses and his successors governed the people in such a way that each of them was ruler over all; so that there was a kind of kingdom. Moreover, seventy-two men were chosen, who were elders in virtue: for it is written (Deuteronomy 1:15): “I took out of your tribes wise and honorable, and appointed them rulers”: so that there was an element of aristocracy. But it was a democratical government in so far as the rulers were chosen from all the people; for it is written (Exodus 18:21): “Provide out of all the people wise [Vulgate: ‘able’] men,” etc.; and, again, in so far as they were chosen by the people; wherefore it is written (Deuteronomy 1:13): “Let me have from among you wise [Vulgate: ‘able’] men,” etc. Consequently it is evident that the ordering of the rulers was well provided for by the Law.”
Saint Thomas recommend that we take the best from monarchy, one empowered but not tyrannical executive, from aristocracy we take the idea that a group of especially able or virtuous persons are set authority that balances and checks the authority of the executive and finally we take from democracy that the people choose the executive and the aristocracy. While the USA does not mirror Thomas’ recommendations perfectly the structure is there. We obviously have a president (executive), a congress (aristocracy) and some sort of democracy (elections). We also all know how distorted all these structures have become in modern America. The power of the executive in some domains (e.g., surveillance of private citizens or prosecution of undeclared wars) has become too huge and unchecked. The aristocracy does not really function most of the time as a group of excellent, virtuous and “able” citizens. And finally our elections, as well know, sometimes do not allow us to really choose our leaders.
The current presidential election is a case in point. Nobody believes we are being given a real choice when presented with Hilary Clinton and Donald Trump. Now more than ever in the USA we need not only a third party but a party informed by Catholic principles –that party is the Solidarity party.