Wherefore, civil society must acknowledge God as its Founder and Parent, and must obey and reverence His power and authority. 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, because the marks of truth are, as it were, engravers upon it. 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. (Leo XIII. Encyclical Libertas praestantissimum, no. 21, June 20, 1888)

As a consequence, the State, constituted as it is, is clearly bound to act up to the manifold and weighty duties linking it to God, by the public profession of religion. Nature and reason, which command every individual devoutly to worship God in holiness, because we belong to Him and must return to Him, since from Him we came, bind also the civil community by a like law. For, men living together in society are under the power of God no less than individuals are, and society, no less than individuals, owes gratitude to God who gave it being and maintains it and whose ever-bounteous goodness enriches it with countless blessings. Since, then, no one is allowed to be remiss in the service due to God, […] So, too, is it a sin for the State not to have care for religion as a something beyond its scope, or as of no practical benefit; or out of many forms of religion to adopt that one which chimes in with the fancy; for we are bound absolutely to worship God in that way which He has shown to be His will. All who rule, therefore, would hold in honour the holy name of God. (Leo XIII. Encyclical Immortale Dei, no. 6, November 1, 1885)

Moreover, if we would judge aright, the supernatural love for the Church and the natural love of our own country proceed from the same eternal principle, since God Himself is their Author and originating Cause. Consequently, it follows that between the duties they respectively enjoin, neither can come into collision with the other. We can, certainly, and should love ourselves, bear ourselves kindly toward our fellow men, nourish affection for the State and the governing powers; but at the same time we can and must cherish toward the Church a feeling of filial piety, and love God with the deepest love of which we are capable. The order of precedence of these duties is, however, at times, either under stress of public calamities, or through the perverse will of men, inverted. For, instances occur where the State seems to require from men as subjects one thing, and religion, from men as Christians, quite another; and this in reality without any other ground, than that the rulers of the State either hold the sacred power of the Church of no account, or endeavor to subject it to their own will. Hence arises a conflict, and an occasion, through such conflict, of virtue being put to the proof. The two powers are confronted and urge their behests in a contrary sense; to obey both is wholly impossible. No man can serve two masters (Mt 6:24), for to please the one amounts to contemning the other. As to which should be preferred no one ought to balance for an instant. It is a high crime indeed to withdraw allegiance from God in order to please men, an act of consummate wickedness to break the laws of Jesus Christ, in order to yield obedience to earthly rulers, or, under pretext of keeping the civil law, to ignore the rights of the Church; ‘we ought to obey God rather than men’ (Acts 5:29). This answer, which of old Peter and the other Apostles were used to give the civil authorities who enjoined unrighteous things, we must, in like circumstances, give always and without hesitation. (Leo XIII. Encyclical Sapientiae christianae, no. 6-7, January 10, 1890)

Now we examine another prolific cause of evils by which, we lament, the Church is at present afflicted, namely indifferentism, or that base opinion which has become prevalent everywhere through the deceit of wicked men, that eternal salvation of the soul can be acquired by any profession of faith whatsoever, if morals are conformed to the standard of the just and the honest. . . . And so from this most rotten source of indifferentism flows that absurd and erroneous opinion, or rather insanity, that liberty of conscience must be claimed and defended for anyone. Indeed, to this most unhealthy error that full and immoderate liberty of opinions which is spreading widely to the destruction of the sacred and civil welfare opens the way, with some men repeatedly asserting with supreme boldness that some advantage flows therefrom to religion itself. (Denzinger-Hünermann 2730-2731. Gregory XVI, Encyclical Mirari vos, no. 10, August 15, 1832)

Your cities are a living part of the Church. There are, in Italy, those who get stir up, for fear that Christianity takes from Cesar that which is of Cesar. As though giving to Cesar what belongs to him was not a command of Jesus; as though laicity of the State, when healthy and legitimate, is not one of the principles of Catholic doctrine; as though it was not the tradition of the Church to make continuous efforts to maintain the distinction, but also – always according to correct principles – the unity of the two powers; as though, on the contrary, the amalgamation of the sacred and the profane had not been proven in history with greater intensity, than when a portion of the faithful separate from the Church. (Pius XII. Address, March 23, 1958)

The Church, the ‘pillar and bulwark of the truth,’ ‘has received this solemn command of Christ from the apostles to announce the saving truth’ (1Tim 3:15; LG 17). ‘To the Church belongs the right always and everywhere to announce moral principles, including those pertaining to the social order, and to make judgments on any human affairs to the extent that they are required by the fundamental rights of the human person or the salvation of souls’ (CIC, can. 747 # 2). (Catechism of the Catholic Church, no. 2032)

Nor can we foresee more joyful omens for religion and the state from the wishes of those who desire that the Church be separated from the State, and that the mutual concord of the government with the sacred ministry be broken. For it is certain that that concord is greatly feared by lovers of this most shameless liberty, which has always been fortunate and salutary for the ecclesiastical and the civil welfare. (Denzinger-Schönmetzer 1615. Gregory XVI, Encyclical Mirari vos, August 15, 1832)

But it is to be lamented that those to whom has been committed the guardianship of the public weal, deceived by the wiles of wicked men and terrified by their threats, have looked upon the Church with a suspicious and even hostile eye, not perceiving that the attempts of the sects would be vain if the doctrine of the Catholic Church and the authority of the Roman Pontiffs had always survived, with the honor that belongs to them, among princes and peoples. (Leo XIII. Encyclical Quod apostolici muneris, December 28, 1878)

In order that these unparalleled benefits might last as long as men should be found on earth, He entrusted to His Church the continuance of His work; and, looking to future times, He commanded her to set in order whatever might have become deranged in human society, and to restore whatever might have fallen into ruin. Although the divine renewal we have spoken of chiefly and directly affected men as constituted in the supernatural order of grace, nevertheless some of its precious and salutary fruits were also bestowed abundantly in the order of nature. (Leo XIII. Encyclical Arcanum divinae sapientiae, On Christian marriage, no. 2-3, February 10, 1880)

These perils to commonwealth, which are before Our eyes, fill Us with grave anxiety, when We behold the security of rulers and the tranquility of empires, together with the safety of nations, put in peril almost from hour to hour. Nevertheless, the divine power of the Christian religion has given birth to excellent principles of stability and order for the State, while at the same time it has penetrated into the customs and institutions of States. And of this power not the least nor last fruit is a just and wise proportion of mutual rights and duties in both princes and peoples. For in the precepts and example of Christ our Lord there is a wonderful force for restraining in their duty as much those who obey as those who rule […] (Leo XIII. Encyclical Diuturnum illud, no. 3, June 29, 1881)

And, indeed, wherever the Church has set her foot she has straightway changed the face of things, and has attempered the moral tone of the people with a new civilization and with virtues before unknown. All nations which have yielded to her sway have become eminent by their gentleness, their sense of justice, and the glory of their high deeds. And yet a hackneyed reproach of old date is levelled against her, that the Church is opposed to the rightful aims of the civil government, and is wholly unable to afford help in spreading that welfare and progress which justly and naturally are sought after by every well-regulated State. From the very beginning Christians were harassed by slanderous accusations of this nature, and on that account were held up to hatred and execration, for being (so they were called) enemies of the Empire. […] This odious calumny, with most valid reason, nerved the genius and sharpened the pen of Saint Augustine, who, notably in his treatise, The City of God, set forth in so bright a light the worth of Christian wisdom in its relation to the public wealth that he seems not merely to have pleaded the cause of the Christians of his day, but to have refuted for all future times impeachments so grossly contrary to truth. The wicked proneness, however, to levy like charges and accusations has not been lulled to rest. Many, indeed, are they who have tried to work out a plan of civil society based on doctrines other than those approved by the Catholic Church. Nay, in these latter days a novel conception of law has begun here and there to gain increase and influence, the outcome, as it is maintained, of an age arrived at full stature, and the result of progressive liberty. But, though endeavours of various kinds have been ventured on, it is clear that no better mode has been devised for the building up and ruling the State than that which is the necessary growth of the teachings of the Gospel. (Leo XIII. Encyclical Immortale Dei, no. 1, November 11, 1885)

One of the salient features of the modern world is the growing interdependence of men one on the other, a development promoted chiefly by modern technical advances. Nevertheless brotherly dialogue among men does not reach its perfection on the level of technical progress, but on the deeper level of interpersonal relationships. These demand a mutual respect for the full spiritual dignity of the person. Christian revelation contributes greatly to the promotion of this communion between persons, and at the same time leads us to a deeper understanding of the laws of social life which the Creator has written into man’s moral and spiritual nature. (Vatican Council II, Pastoral Constitution Gaudium et spes, no. 23, December 7, 1965)

The Church receives from the Gospel the full revelation of the truth about man. When she fulfills her mission of proclaiming the Gospel, she bears witness to man, in the name of Christ, to his dignity and his vocation to the communion of persons. She teaches him the demands of justice and peace in conformity with divine wisdom. The Church makes a moral judgment about economic and social matters, ‘when the fundamental rights of the person or the salvation of souls requires it’ (Gaudium et Spes, 76). In the moral order she bears a mission distinct from that of political authorities: the Church is concerned with the temporal aspects of the common good because they are ordered to the sovereign Good, our ultimate end. She strives to inspire right attitudes with respect to earthly goods and in socio-economic relationships. (Catechism of the Catholic Church, no. 2419-2420)

Wherefore if the true God is worshipped, and if He is served with genuine rites and true virtue, it is advantageous that good men should long reign both far and wide. Nor is this advantageous so much to themselves, as to those over whom they reign. For, so far as concerns themselves, their piety and probity, which are great gifts of God, suffice to give them true felicity, enabling them to live well the life that now is, and afterwards to receive that which is eternal. In this world, therefore, the dominion of good men is profitable, not so much for themselves as for human affairs. But the dominion of bad men is hurtful chiefly to themselves who rule, for they destroy their own souls by greater license in wickedness; while those who are put under them in service are not hurt except by their own iniquity. For to the just all the evils imposed on them by unjust rulers are not the punishment of crime, but the test of virtue. Therefore the good man, although he is a slave, is free; but the bad man, even if he reigns, is a slave, and that not of one man, but, what is far more grievous, of as many masters as he has vices; of which vices when the divine Scripture treats, it says, ‘For of whom any man is overcome, to the same he is also the bond-slave’ (2Pet 2:19). (Saint Augustine. City of God, Book IV, Ch. 3)

Accordingly, two cities have been formed by two loves: the earthly by the love of self, even to the contempt of God; the heavenly by the love of God, even to the contempt of self. The former, in a word, glories in itself, the latter in the Lord. For the one seeks glory from men; but the greatest glory of the other is God, the witness of conscience. The one lifts up its head in its own glory; the other says to its God, ‘Thou art my glory, and the lifter up of mine head’ (Ps 3:3). In the one, the princes and the nations it subdues are ruled by the love of ruling; in the other, the princes and the subjects serve one another in love, the latter obeying, while the former take thought for all. The one delights in its own strength, represented in the persons of its rulers; the other says to its God, ‘I will love Thee, O Lord, my strength’ (Ps 18:1). And therefore the wise men of the one city, living according to man, have sought for profit to their own bodies or souls, or both, and those who have known God ‘glorified Him not as God, neither were thankful, but became vain in their imaginations, and their foolish heart was darkened; professing themselves to be wise,’—that is, glorying in their own wisdom, and being possessed by pride, — ‘they became fools, and changed the glory of the incorruptible God into an image made like to corruptible man, and to birds, and four-footed beasts, and creeping things. For they were either leaders or followers of the people in adoring images, ‘and worshipped and served the creature more than the Creator, who is blessed for ever’ (Rom 1:21-25). But in the other city there is no human wisdom, but only godliness, which offers due worship to the true God, and looks for its reward in the society of the saints, of holy angels as well as holy men, ‘that God may be all in all’ (1 Cor 15:28). (Saint Augustine. City of God, Book XIV, Ch. 28)

The Holy Gospel narrates that when Jesus was crucified ‘there was darkness over the whole earth’ (Mt 27:45); a terrifying symbol of what happened and what still happens spiritually wherever incredulity, blind and proud of itself, has succeeded in excluding Christ from modern life, especially from public life, and has undermined faith in God as well as faith in Christ. The consequence is that the moral values by which in other times public and private conduct was gauged have fallen into disuse; and the much vaunted civilization of society, which has made ever more rapid progress, withdrawing man, the family and the State from the beneficent and regenerating effects of the idea of God and the teaching of the Church, has caused to reappear, in regions in which for many centuries shone the splendors of Christian civilization, in a manner ever clearer, ever more distinct, ever more distressing, the signs of a corrupt and corrupting paganism: ‘There was darkness when they crucified Jesus’. Many perhaps, while abandoning the teaching of Christ, were not fully conscious of being led astray by a mirage of glittering phrases, which proclaimed such estrangement as an escape from the slavery in which they were before held; nor did they then foresee the bitter consequences of bartering the truth that sets free, for error which enslaves. They did not realize that, in renouncing the infinitely wise and paternal laws of God, and the unifying and elevating doctrines of Christ’s love, they were resigning themselves to the whim of a poor, fickle human wisdom; they spoke of progress, when they were going back; of being raised, when they groveled; of arriving at man’s estate, when they stooped to servility. They did not perceive the inability of all human effort to replace the law of Christ by anything equal to it; ‘they became vain in their thoughts’ (Rom 1:21). With the weakening of faith in God and in Jesus Christ, and the darkening in men’s minds of the light of moral principles, there disappeared the indispensable foundation of the stability and quiet of that internal and external, private and public order, which alone can support and safeguard the prosperity of States. (Pius XII. Encyclical Summi pontificatus, no. 23-25, October 20, 1939)

Thereupon there came into being and spread far and wide throughout the world that doctrine of rationalism or naturalism, – utterly opposed to the christian religion, since this is of supernatural origin, – which spares no effort to bring it about that Christ, who alone is our lord and saviour, is shut out from the minds of people and the moral life of nations. Thus they would establish what they call the rule of simple reason or nature. The abandonment and rejection of the christian religion, and the denial of God and his Christ, has plunged the minds of many into the abyss of pantheism, materialism and atheism, and the consequence is that they strive to destroy rational nature itself, to deny any criterion of what is right and just, and to overthrow the very foundations of human society. With this impiety spreading in every direction, it has come about, alas, that many even among the children of the catholic church have strayed from the path of genuine piety, and as the truth was gradually diluted in them, their catholic sensibility was weakened. (Vatican Council I, Session 3, Dogmatic Constitution Filius Dei, Session III, April 24 1870)

Justice being taken away, then, what are kingdoms but great robberies? For what are robberies themselves, but little kingdoms? The band itself is made up of men; it is ruled by the authority of a prince, it is knit together by the pact of the confederacy; the booty is divided by the law agreed on. If, by the admittance of abandoned men, this evil increases to such a degree that it holds places, fixes abodes, takes possession of cities, and subdues peoples, it assumes the more plainly the name of a kingdom, because the reality is now manifestly conferred on it, not by the removal of covetousness, but by the addition of impunity. Indeed, that was an apt and true reply which was given to Alexander the Great by a pirate who had been seized. For when that king had asked the man what he meant by keeping hostile possession of the sea, he answered with bold pride, ‘What thou meanest by seizing the whole earth; but because I do it with a petty ship, I am called a robber, whilst thou who dost it with a great fleet art styled emperor’. (Saint Augustine. City of God, Book IV, Ch. 4)