Especially with reference to the so-called ‘liberties’ which are so greatly coveted in these days, all must stand by the judgment of the apostolic see, and have the same mind. Let no man be deceived by the honest outward appearance of these liberties, but let each one reflect whence these have had their origin, and by what efforts they are everywhere upheld and promoted. Experience has made Us well acquainted with their results to the State, since everywhere they have borne fruits which the good and wise bitterly deplore. If there really exist anywhere, or if we in imagination conceive, a State, waging wanton and tyrannical war against Christianity, and if we compare with it the modern form of government just described, this latter may seem the more endurable of the two. Yet, undoubtedly, the principles on which such a government is grounded are, as We have said, of a nature which no one can approve.

–Leo XIII, Immortale Dei 42

Now, when the State rests on foundations like those just named–and for the time being they are greatly in favor–it readily appears into what and how unrightful a position the Church is driven. For, when the management of public business is in harmony with doctrines of such a kind, the Catholic religion is allowed a standing in civil society equal only, or inferior, to societies alien from it; no regard is paid to the laws of the Church, and she who, by the order and commission of Jesus Christ, has the duty of teaching all nations, finds herself forbidden to take any part in the instruction of the people. With reference to matters that are of twofold jurisdiction, they who administer the civil power lay down the law at their own will, and in matters that appertain to religion defiantly put aside the most sacred decrees of the Church. They claim jurisdiction over the marriages of Catholics, even over the bond as well as the unity and the indissolubility of matrimony. They lay hands on the goods of the clergy, contending that the Church cannot possess property. Lastly, they treat the Church with such arrogance that, rejecting entirely her title to the nature and rights of a perfect society, they hold that she differs in no respect from other societies in the State, and for this reason possesses no right nor any legal power of action, save that which she holds by the concession and favor of the government. If in any State the Church retains her own agreement publicly entered into by the two powers, men forthwith begin to cry out that matters affecting the Church must be separated from those of the State.

Their object in uttering this cry is to be able to violate unpunished their plighted faith, and in all things to have unchecked control. And as the Church, unable to abandon her chiefest and most sacred duties, cannot patiently put up with this, and asks that the pledge given to her be fully and scrupulously acted up to, contentions frequently arise between the ecclesiastical and the civil power, of which the issue commonly is that the weaker power yields to the one which is stronger in human resources.

Accordingly, it has become the practice and determination under this condition of public polity (now so much admired by many) either to forbid the action of the Church altogether, or to keep her in check and bondage to the State. Public enactments are in great measure framed with this design. The drawing up of laws, the administration of State affairs, the godless education of youth, the spoliation and suppression of religious orders, the overthrow of the temporal power of the Roman Pontiff, all alike aim to this one end-to paralyse the action of Christian institutions, to cramp to the utmost the freedom of the Catholic Church, and to curtail her ever single prerogative.

Now, natural reason itself proves convincingly that such concepts of the government of a State are wholly at variance with the truth. Nature itself bears witness that all power, of every kind, has its origin from God, who is its chief and most august source.

–Leo XIII, Immortale Dei 27-30

Amongst these principles [which, in the midst of the terrible unheavals of the last century, were wildly conceived and boldly proclaimed] the main one lays down that as all men are alike by race and nature, so in like manner all are equal in the control of their life; that each one is so far his own master as to be in no sense under the rule of any other individual; that each is free to think on every subject just as he may choose, and to do whatever he may like to do; that no man has any right to rule over other men. In a society grounded upon such maxims all government is nothing more nor less than the will of the people, and the people, being under the power of itself alone, is alone its own ruler. It does choose, nevertheless, some to whose charge it may commit itself, but in such wise that it makes over to them not the right so much as the business of governing, to be exercised, however, in its name.

The authority of God is passed over in silence, just as if there were no God; or as if He cared nothing for human society; or as if men, whether in their individual capacity or bound together in social relations, owed nothing to God; or as if there could be a government of which the whole origin and power and authority did not reside in God Himself. Thus, as is evident, a State becomes nothing but a multitude which is its own master and ruler. And since the people is declared to contain within itself the spring-head of all rights and of all power, it follows that the State does not consider itself bound by any kind of duty toward God. Moreover, it believes that it is not obliged to make public profession of any religion; or to inquire which of the very many religions is the only one true; or to prefer one religion to all the rest; or to show to any form of religion special favour; but, on the contrary, is bound to grant equal rights to every creed, so that public order may not be disturbed by any particular form of religious belief.

–Leo XIII, Immortale Dei 24-25 [23]

First and foremost, it is the duty of all Catholics worthy of the name and wishful to be known as most loving children of the Church, to reject without swerving whatever is inconsistent with so fair a title; to make use of popular institutions, so far as can honestly be done, for the advancement of truth and righteousness; to strive that liberty of action shall not transgress the bounds marked out by nature and the law of God; to endeavour to bring back all civil society to the pattern and form of Christianity which We have described. It is barely possible to lay down any fixed method by which such purposes are to be attained, because the means adopted must suit places and times widely differing from one another. Nevertheless, above all things, unity of aim must be preserved, and similarity must be sought after in all plans of action. Both these objects will be carried into effect without fail if all will follow the guidance of the apostolic see as their rule of life and obey the bishops whom the Holy Spirit has placed to rule the Church of God.  The defense of Catholicism, indeed, necessarily demands that in the profession of doctrines taught by the Church all shall be of one mind and all steadfast in believing; and care must be taken never to connive, in any way, at false opinions, never to withstand them less strenuously than truth allows. In mere matters of opinion it is permissible to discuss things with moderation, with a desire of searching into the truth, without unjust suspicion or angry recriminations.

–Leo XIII, Immortale Dei 46

Catholics have just reasons for taking part in the conduct of public affairs. For in so doing they assume not nor should they assume the responsibility of approving what is blameworthy in the actual methods of government, but seek to turn these very methods, so far as is possible, to the genuine and true public good, and to use their best endeavours at the same time to infuse, as it were, into all the veins of the State the healthy sap and blood of Christian wisdom and virtue. The morals and ambitions of the heathens differed widely from those of the Gospel, yet Christians were to be seen living undefiled everywhere in the midst of pagan superstition, and, while always true to themselves, coming to the front boldly wherever an opening was presented. Models of loyalty to their rulers, submissive, so far as was permitted, to the sovereign power, they shed around them on every side a halo of sanctity; they strove to be helpful to their brethren, and to attract others to the wisdom of Jesus Christ, yet were bravely ready to withdraw from public life, nay, even to lay down their life, if they could not without loss of virtue retain honours, dignities, and offices.

–Leo XIII, Immortale Dei 45