Much of this post will be old news for reactionaries, but it bears occasional reiteration. The tl;dr is as follows: It is a matter of divine revelation, and therefore binding on Christians to believe, that the rule of law was ordained by God and thus that political authority derives from his institution of the state as the minister of divine justice. This doesn’t rule out, for instance, belief that democracy or anything else is the best (because most prudent) arrangement for the governance of society; but it certainly rules out the belief that democracy-or-anything-else is a moral imperative and that the legitimacy of the state is altogether dependent on one such choice to the exclusion of all others.
Consider the flood narrative in the Book of Genesis, chapters 6 through 9. The wickedness of man after the Fall had grown so great that God resolved to wipe him out with a flood, sparing only the virtuous Noah and his family by instructing him to build an ark. Afterward, God forged his covenant with Noah, the first of a succession of covenants after the fall, which includes this line:
“Whosoever shall shed man’ s blood, his blood shall be shed: for man was made to the image of God.” (Gen. 9:6)
Now, consider the context. The wickedness of man and the injuries which he inflicted by his sins upon the order of justice was so great that it necessitated, on God’s part, a dramatic, restorative intervention. This he does not wish to do again (“all flesh shall be no more destroyed with the waters of a flood, neither shall there be from henceforth a flood to waste the earth”; Gen. 9:11), but if he is to refrain from such interventions in the future, it will be necessary that his justice be enacted by someone else. Thus, we understand Genesis 9:6 as representing God’s institution of the rule of law for the good of man and the maintenance of the divinely-appointed order of justice. For this reason, St. Paul reminds us, in his epistle to the Romans, that the prince “is God’s minister” who “beareth not the sword in vain” (Romans 13:4), and likewise, St. Peter exhorts the Church to be “subject therefore to every human creature for God’s sake: whether it be to the king as excelling; Or to governors as sent by him for the punishment of evildoers, and for the praise of the good: For so is the will of God” (1 Peter 2:13-14). St. Peter goes on to oblige the Church to “Honour the king” (1 Peter 2:17), the very same emperor whose minister, Pontius Pilate, ordered the execution of Christ, and in whose name the various persecutions of the Church would be authorized. And we must not forget that Christ himself was ever obedient to earthly authorities, first his parents (“And he went down with [Joseph and Mary], and came to Nazareth, and was subject to them”; Luke 2:54) and then to Pilate, whose judgments he obeyed and whose questions he answered, an obedience he often refused to the priests, whose questions he routinely answered with stony silence.
So it is, effectively, a matter of direct, public, divine revelation — commanded by God, exemplified by Christ, recorded in Scripture, and supported by the near-unanimous witness of the saints — that the authority of the state to rule, to expect obedience to its rule, and to enforce justice against the wicked, is given it by God. It is remarkably difficult, indeed, to see how one could dispute such a revealed truth and continue to call oneself “Christian”; as Christ himself sardonically asked his less-committed followers, “And why call you me, Lord, Lord; and do not the things which I say?” (Luke 6:46). We cannot achieve salvation without recognizing Christ as Lord; and we cannot recognize him as Lord if we do not do as he says.
Now the exact form which the exercise of political authority takes in any particular culture or time will naturally vary according to the dictates of prudence, the needs of the polity, and the general character of its unwritten constitution. Thus, Christians may disagree in good faith about the relative merits of democracy as a prudential arrangement for providing for the rule of law. But they are absolutely forbidden from buying into any of the legitimating narratives for these arrangements typically expounded by their modern apologists, much less from attempting to situate these narratives within a Christian ethos.
Put simply, you cannot be a Christian of good faith and believe that the political authority of states in general or any given state in particular derives from the consent of the governed, from technocratic or rational considerations, from the inevitable unfolding of historical processes, or from the natural superiority of one’s party, race, or class. Such beliefs are the matter of heresy, and one who subscribes to them suffers shipwreck in the faith.