27 Now, from the disturbing errors which We have described the greatest dangers to States are to be feared. For, the fear of God and reverence for divine laws being taken away, the authority of rulers despised, sedition permitted and approved, and the popular passions urged on to lawlessness, with no restraint save that of punishment, a change and overthrow of all things will necessarily follow. Yea, this change and overthrow is deliberately planned and put forward by many associations of communists and socialists; and to their undertakings the sect of Freemasons is not hostile, but greatly favours their designs, and holds in common with them their chief opinions. And if these men do not at once and everywhere endeavour to carry out their extreme views, it is not to be attributed to their teaching and their will, but to the virtue of that divine religion which cannot be destroyed; and also because the sounder part of men, refusing to be enslaved to secret societies, vigorously resist their insane attempts.
Source: Humanum Genus (Vatican.va)