It is often asserted that the Christian societies of old were oppressive, torturous regimes stifling human freedom. This is false. Witness the countless sermons preached by the saints against the worldliness of their day. Men were not forced to go to Mass at the point of a spear. Rather, in a Christian society, there is simply the worship of Christ as King. The laws, customs, and culture strive to be in accord with the Catholic faith. Only the Christian state provides what is necessary for man in his fallen state, promotes his true end, and protects the weak and vulnerable.
Man’s True State Is Original Sin
A Christian state begins with a true assessment of the current state of man: he bears the stain and effect of Original Sin. His intellect is darkened, his will is weakened, and he is inclined to evil. Man being born into this condition, the Christian state gives him a structure of authority — from the government to the Church to the family — that refers back to God. Thus, the entire fabric of a Christian society is oriented in the opposite direction of man’s inclinations to evil, creating a social momentum toward what is truly good.
This cultural framework must guide every person through childhood and into adulthood and ultimately to eternal beatitude. Since man’s burden is Original Sin, the Christian state promotes and supports the institution that provides its cure: the Catholic Church. With the assistance of divine grace and the teleological hierarchy of Christian society, man can overcome Original Sin and strive to attain his final end. Thus, both the state in the natural realm and the Church in the supernatural confess the dominion of one lord over both: Christ the King.
The King has solemnly said:
All power is given to me in heaven and in earth. Going therefore, teach ye all nations; baptizing them in the name of the Father, and of the Son, and of the Holy Ghost. Teaching them to observe all things whatsoever I have commanded you. (Mt. 28:18–20)
Summing up the teachings of multiple popes before after him, Leo XIII writes:
Justice therefore forbids, and reason itself forbids, the State to be godless; or to adopt a line of action which would end in godlessness-namely, to treat the various religions (as they call them) alike, and to bestow upon them promiscuously equal rights and privileges. Since, then, the profession of one religion is necessary in the State, that religion must be professed which alone is true, and which can be recognized without difficulty, especially in Catholic States[.] … This religion, therefore, the rulers of the State must preserve and protect, if they would provide — as they should do — with prudence and usefulness for the good of the community. For public authority exists for the welfare of those whom it governs; and, although its proximate end is to lead men to the prosperity found in this life, yet, in so doing, it ought not to diminish, but rather to increase, man’s capability of attaining to the supreme good in which his everlasting happiness consists: which never can be attained if religion be disregarded. 
Moreover, the Christian state protects the vulnerable and the weak, particularly children, who are quickly influenced by outside pressures. The family that raises the child in a Christian society is reinforced by the culture toward allegiance to and freedom in Christ the King. The child need not doubt that Christ is King to whom he owes his life and allegiance. The child is safe from error and feels cultural shame to entertain thoughts against this allegiance. The society reinforces what is taught in the home, so the child is not conflicted by multiple sources of authority, since every authority in the family, state, and Church has one principle: Christ the King.
Pre-Christian societies no matter how disordered, still refer all authority back to a supernatural principle, implicitly confirming the dogma of Original Sin — that man cannot attain beatitude without the aid of the divine. Thus can Leo XIII quickly dismiss the separation of Church and State as a “manifest absurdity” based solely upon natural reason:
Nature herself proclaims the necessity of the State providing means and opportunities whereby the community may be enabled to live properly, that is to say, according to the laws of God. For, since God is the source of all goodness and justice, it is absolutely ridiculous that the State should pay no attention to these laws or render them abortive by contrary enact menu. 
When a pre-Christian society is baptized and made into a Christian state — the process accomplished and promoted by countless saints, from Gregory the Illuminator in Armenia to St. Patrick in Ireland — then can man’s feeble groping for truth and freedom be given true liberation from the bondage to the devil. Man needs the state to confess Christ the King — otherwise, he will call the state itself the king.
Modern Secular Society Is Founded on a False Notion of Man
This brings us to the contrasting notion of modern, secular democracy. The presupposition of this political system denies the reality of the Original Sin and the need for divine grace. In the Hobbes-Lockean understanding, man overcomes his own “state of nature” by forming societies in order to check the excesses of evil men. In the modern secular theory, man does not need Christ the King for his beatitude, but rather needs a different savior: the secular state.
The idea preached by so many revolutionaries to their supporters is this: if only you had political change X or legal change Y, then you could be truly happy and truly free. This is an error, since man, afflicted with Original Sin, can never be free or happy without the grace of Jesus Christ, no matter what political system obtains. Thus does the secular democracy tend to impose its own political organization as a replacement for the sacramental system of divine grace from the Catholic Church. In the modern system, there is no need for Christ the King. The state itself is God.
Social Results of Denying Original Sin
We see this is modern America. A great portion of citizens have a college education, but, blinded by their passions, there are still millions who cannot understand that a fetus is a human being. Indeed, there is no historical precedent for the modern mass slaughter of innocent children.
Instead of a cultural orientation against the inclinations of Original Sin, the modern culture reinforces these evil inclinations. This brings us to another failure of the secular democracy: morality by majority vote. Because Original Sin is denied, if the majority believe something, it must be right. This is similar to the error of “might makes right.”
But by the dogma of Original Sin, the popular will tends toward what is evil. Since men are ruled by their passions, it is easy for them to be manipulated in their emotions by a viral video or a shocking statement. Witness the endless emotional provocations that pervade the media and advertising. Appeals to reason are much less profitable than emotionalism.
The Modern State Does Not Protect the Weak and Vulnerable
The measure of any society in the natural order is the way in which it protects its most vulnerable members. Even beyond the slaughter of innocent children and abandoning others to nefarious gender theory, the modern state is oriented toward reinforcing the inclinations of every man toward himself alone. Children are especially vulnerable to this. This is the sovereignty of the individual will, enshrined in the majority vote. When the rights of man trump the rights of Christ the King, man becomes a slave to his own passions. The words of Cahill are as relevant today as they were in 1932:
Seeing that the powerful frequently are able to secure in their own favor the decision of the majority, through the operation of finance and of the press, personal rights have in practice little more security in the Liberal [Secular] State than under the old pagan regime. Thus arise the exploitation of the poor and the tyranny of the monied interest. 
In our time, the tech and media giants control the information that informs the masses. As any Catholic parent will know, we must have constant vigilance to protect our children from the evils of secular society. From media and advertising to television and movies, most seek to provoke the passions of our children in order to lead them astray. There is only so much a parent can do in our society.
With the influence of Jacques Maritain and the heretic Teilhard de Chardin, a gradual error crept into the Church that either denied Original Sin or dismissed its effects in practice. Thus did Vatican II and Paul VI pursue with great optimism a hopeful dialogue with modernity and cooperation with the secular state. Now, a few generations removed, this dialogue has continued to receive greater scrutiny. In short, we must face the evil fruit and bloodshed that has come from the secular state after some two hundred years, as well as this recent dialogue, and weigh these facts with the words of the popes who have faced this political movement since the 18th century. With the feast of Christ the King fresh in our memories, let the words of Pius XI suffice:
When once men recognize, both in private and in public life, that Christ is King, society will at last receive the great blessings of real liberty, well-ordered discipline, peace and harmony. 
 Leo XIII, Libertas (1888), 21
 Ibid., 18
 Rev. E. Cahill, S.J., The Framework of a Christian State (Roman Catholic Books reprint 1932), 454
 Pius XI, Quas Primas (1925), 19