4 The right to rule is not necessarily, however, bound up with any special mode of government. It may take this or that form, provided only that it be of a nature of the government, rulers must ever bear in mind that God is the paramount ruler of the world, and must set Him before themselves as their exemplar and law in the administration of the State. For, in things visible God has fashioned secondary causes, in which His divine action can in some wise be discerned, leading up to the end to which the course of the world is ever tending. In like manner, in civil society, God has always willed that there should be a ruling authority, and that they who are invested with it should reflect the divine power and providence in some measure over the human race.
Source: Immortale Dei (Vatican.va)