Pope Pius IX warned the world of the Evils of Communism 68 years before Fatima

Written the year following the publication of the Communist Manifesto
18. As regards this teaching and these theories, it is now generally known that the special goal of their proponents is to introduce to the people the pernicious fictions of Socialism and Communism by misapplying the terms “liberty” and “equality.” The final goal shared by these teachings, whether of Communism or Socialism, even if approached differently, is to excite by continuous disturbances workers and others, especially those of the lower class, whom they have deceived by their lies and deluded by the promise of a happier condition. They are preparing them for plundering, stealing, and usurping first the Church’s and then everyone’s property. After this they will profane all law, human and divine, to destroy divine worship and to subvert the entire ordering of civil societies.

6. You are aware indeed, that the goal of this most iniquitous plot is to drive people to overthrow the entire order of human affairs and to draw them over to the wicked theories of this Socialism and Communism, by confusing them with perverted teachings. But these enemies realize that they cannot hope for any agreement with the Catholic Church, which allows neither tampering with truths proposed by faith, nor adding any new human fictions to them. This is why they try to draw the Italian people over to Protestantism, which in their deceit they repeatedly declare to be only another form of the same true religion of Christ, thereby just as pleasing to God. Meanwhile they know full well that the chief principle of the Protestant tenets, i.e., that the holy scriptures are to be understood by the personal judgment of the individual, will greatly assist their impious cause. They are confident that they can first misuse the holy scriptures by wrong interpretation to spread their errors and claim God’s authority while doing it. Then they can cause men to call into doubt the common principles of justice and honor.

25. But if the faithful scorn both the fatherly warnings of their pastors and the commandments of the Christian Law recalled here, and if they let themselves be deceived by the present-day promoters of plots, deciding to work with them in their perverted theories of Socialism and Communism, let them know and earnestly consider what they are laying up for themselves. The Divine Judge will seek vengeance on the day of wrath. Until then no temporal benefit for the people will result from their conspiracy, but rather new increases of misery and disaster. For man is not empowered to establish new societies and unions which are opposed to the nature of mankind. If these conspiracies spread throughout Italy there can only be one result: if the present political arrangement is shaken violently and totally ruined by reciprocal attacks of citizens against citizens by their wrongful appropriations and slaughter, in the end some few, enriched by the plunder of many, will seize supreme control to the ruin of all.