Political-philosophy types should all be familiar with Plato’s belief that the “philosopher king” would be the best ruler. The problem is you can never find him.

Picking up on that theme, Thomas Aquinas delves into the best form of government in On Kingship (De Regno). For all of us living in America, we probably would be surprised to learn about what he thought was the best form of government. Somewhat like Plato, he believed that monarchy was best. The reasons?

  • Aquinas believed that “the aim of any ruler should be directed towards securing the welfare of that which he undertakes to rule” and that a king would be the best to do so – much like the captain of a ship.   
  • If there is rule by many, then the government and country are prone to disunity. As Aquinas argues, “for union is necessary among them if they are to rule at all: several men, for instance, could not pull a ship in one direction unless joined together in some fashion.” And so he believed one man is better at keeping a country united.
  • He also believed that rule by one is the natural order of things. As he writes, “whatever is in accord with nature is best, for in all things nature does what is best. Now, every natural governance is governance by one.”
  • History, to Aquinas, shows that the natural order is to have a king: “For provinces or cities which are not ruled by one person are torn with dissensions and tossed about without peace…”

In other areas of On Kingship, Aquinas elaborates as to the character of this king. He should have a “zeal for justice”, “the gentleness of clemency”, and “mildness” when it comes to the “individuals who are subject to his rule”. In other words, Aquinas sees a sort of “philosopher king” as the best ruler as well.

But Aquinas is no fool. As much as a monarchy may be the best form of government with a “philosopher king” at the head, the system of rule by one man can also be the very worst form of government if a tyrant is at the head.

“If an unjust government is carried on by one man alone, who seeks his own benefit from his rule and not the good of the multitude subject to him, such a ruler is called a tyrant—a word derived from strength—because he oppresses by might instead of ruling by justice.”

Because power is centralized in a monarchy, if a tyrant rules the throne he is able to efficiently and effectively pursue his own good over that of his people. That is also why people reflexively hate the idea of monarchy – even if ruled by the “philosopher king”, as Aquinas admits:

“Because both the best and the worst government are latent in monarchy, i.e. in the rule of one man, the royal dignity is rendered hateful to many people on account of the wickedness of tyrants. Some men, indeed, whilst they desire to be ruled by a king, fall under the cruelty of tyrants, and not a few rulers exercise tyranny under the cloak of royal dignity”

As for other forms of government? Aquinas considered them all to be different forms of “polyarchy” or rule by many, including aristocracy, oligarchy, democracy, and a republic. Aquinas believed that the core problem of “polyarchy” is disunity:

“Group government [polyarchy] most frequently breeds dissension.”

And to Aquinas, where does the dissension and disunity lead? Tyranny.

“Moreover, in point of fact, a polyarchy deviates into tyranny not less but perhaps more frequently than a monarchy. When, on account of there being many rulers, dissensions arise in such a government, it often happens that the power of one preponderates and he then usurps the government of the multitude for himself. This indeed may be clearly seen from history. There has hardly ever been a polyarchy that did not end in tyranny. The best illustration of this fact is the history of the Roman Republic. It was for a long time administered by the magistrates but then animosities, dissensions and civil wars arose and it fell into the power of the most cruel tyrants. In general, if one carefully considers what has happened in the past and what is happening in the present, he will discover that more men have held tyrannical sway in lands previously ruled by many rulers than in those ruled by one.”

The Founders of America certainly recognized all of these ideas as well as the historical precedent as they set about creating our government with its checks and balances against the centralization of power. But we should also remember Benjamin Franklin’s response to the woman’s question of whether or not we would have a republic or a monarchy as a government at the end of the Constitutional Convention of 1787:

“A Republic, if you can keep it.”