Encyclical letter of Pope leo xiii, issued Nov. 1, 1885; frequently entitled in English "The Christian Constitution of States," after a phrase from the final paragraph. It was one of a long series of letters that Leo wrote on the political order, whose declared aim was "to contrast with the lessons taught by Christ the novel theories now advanced touching the State" (par. 2). Scholars agree that it contains the most complete exposition and clarification of Leo's teaching on the problem of church and state.
During the 19th century the concept of "the modern state" became widely accepted in many parts of Europe. "Liberal democracy" was the most common of the many terms used to describe it. It is a state governed by elected representatives of the people; maintaining neutrality on questions of religion, professing neither to support nor to suppress any particular creed or cult; considering public, nonreligious education to be the business of the state; recognizing as valid only those marriages which are contracted according to civil regulations; providing for divorce and the remarriage of divorced persons; sponsoring freedom of speech and press, completely rejecting government censorship. Many Catholics in Europe, especially in France, wondered whether a good Catholic could actively support the modern state. The encyclical set forth some broad principles to help Catholics answer the question; in addition, it included some particular directives relevant to the actual situation in France.
Unless studied in its proper context, and in the light of the full papal teaching on the political order, Immortale Dei can be easily misunderstood by present readers. The following generalizations indicate its contents: The Church is not opposed to the rightful aims of civil government. Any mode of government is legitimate as long as rulers govern with justice and for the common good. Since the authority of the state, like all authority, is from God, the state must acknowledge its indebtedness to God by professing religion and indeed the true religion, which is not hard to discover. God has established two powers: the ecclesiastical power set over divine things and the civil power set over human things. Since each of these two powers has authority over the same subjects, there should exist between them a certain orderly connection and collaboration; the contemporary doctrine that favors their separation is absurd. It must be remembered that the Church is the true and sole guardian of morals. Individual Catholics must cooperate with any form of government that is not obviously immoral. By thus restating traditional teaching and noting the legitimacy of differences among Catholics "in matters merely political" (par. 49), Leo made it clear that the Church was not opposed to the ascendant democracy, even though it deplored its tolerance or legalization of certain social evils.
[d. l. lowery]
"Immortale Dei." New Catholic Encyclopedia. . Encyclopedia.com. (December 11, 2018). https://www.encyclopedia.com/religion/encyclopedias-almanacs-transcripts-and-maps/immortale-dei
"Immortale Dei." New Catholic Encyclopedia. . Retrieved December 11, 2018 from Encyclopedia.com: https://www.encyclopedia.com/religion/encyclopedias-almanacs-transcripts-and-maps/immortale-dei