To be more explicit, Freemasonry. Since Freemasons were very prominent in the founding of the US, the vatican has a special place in it's heart for us.
http://en.wikipedia.org/wiki/Quaesitum_estMore detail here:
http://www.masonicdictionary.com/humanum.html-snip-
13. In those matters which regard religion let it be seen how the sect of the Freemasons acts, especially where it is more free to act without restraint, and then let any one judge whether in fact it does not wish to carry out the policy of the naturalists. By a long and persevering labor, they endeavor to bring about this result-namely, that the teaching office and authority of the Church may become of no account in the civil State; and for this same reason they declare to the people and contend that Church and State ought to be altogether disunited. By this means they reject from the laws and from the commonwealth thewholesome influence of the Catholic religion; and they consequently imagine that States ought to be constituted without any regard for the laws and precepts of the Church.
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22. Then come their doctrines of politics, in which the naturalists lay down that all men have the same right, and are in every respect of equal and like condition; that each one is naturally free; that no one has the right to command another; that it is an act of violence to require men to obey any authority other than that which is obtained from themselves. According to this, therefore, all things belong to the free people; power is held by the command or permission of the people, so that, when the popular will changes, rulers may lawfully be deposed and the source of all rights and civil duties is either in the multitude or in the governing authority when this is constituted according to the latest doctrines. It is held also that the State should be without God; that in the various forms of religion there is no reason why one should have precedence of another; and that they are all to occupy the same place.
23. That these doctrines are equally acceptable to the Freemasons, and that they would wish to constitute States according to this example and model, is too well known to require proof. For some time past they have openly endeavoured to bring this about with all their strength and resources; and in this they prepare the way for not a few bolder men who are hurrying on even to worse things, in their endeavor to obtain equality and community of all goods by the destruction of every distinction of rank and property.
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26. In like manner, no one doubts that all men are equal one to another, so far as regards their common origin and nature, or the last end which each one has to attain, or the rights and duties which are thence derived. But, as the abilities of all are not equal, as one differs from another in the powers of mind or body, and as there are very many dissimilarities of manner, disposition, and character, it is most repugnant to reason to endeavor to confine all within the same measure, and to extend complete equality to the institutions of civic life. Just as a perfect condition of the body results from the conjunction and composition of its various members, which, though differing in form and purpose, make, by their union and the distribution of each one to its proper place, a combination beautiful to behole, firm in strength, and necessary for use; so, in the commonwealth, there is an almost infinite dissimilarity of men, as parts of the whole. If they are to be all equal, and each is to follow his own will, the State will appear most deformed; but if, with a distinction of degrees of dignity, of pursuits and employments, all aptly conspire for the common good, they will present the image of a State both well constituted and conformable to nature.
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35. In the third place, there is a matter wisely instituted by our forefathers, but in course of time laid aside, which may now be used as a pattern and form of something similar. We mean the associations of guilds of workmen, for the protection, under the guidance of religion, both of their temporal interests and of their morality. If our ancestors, by long use and experience, felt the benefit of these guilds, our age perhaps will feel it the more by reason of the opportunity which they will give of crushing the power of the sects. Those who support themselves by the labour of their hands, besides being, by their very condition, most worthy above all others of charity and consolation, are also especially exposed to the allurements of men whose ways lie in fraud and deceit. Therefore, they ought to be helped with the greatest possible kindness, and to be invited to join associations that are good, lest they be drawn away to others that are evil. For this reason, We greatly wish, for the salvation of the people, that, under the auspices and patronage of the bishops, and at convenient times, these gilds may be generally restored. To Our great delight, sodialities of this kind and also associations of masters have in many places already been established, having, each class of them, for their object to help the honest workman, to protect and guard his children and family, and to promote in them piety, Christian knowledge, and a moral life. And in this matter We cannot omit mentioning that exemplary society, named after its founder, St. Vincent, which has deserved so well of the lower classes. Its acts and its aims are well known. Its whole object is to give relief to the poor and miserable. This it does with singular prudence and modesty; and the less it wishes to be seen, the better is it fitted for the exercise of Christian charity, and for the relief of suffering.
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Lots more in the document and other Papal Bulls.