Liberalism is the root of heresy, the tree of evil in whose branches all the harpies of infidelity find ample shelter; it is today the evil of all evils.
“The theater, literature, public and private morals are all saturated with obscenity and impurity. The result is inevitable; a corrupt generation necessarily begets a revolutionary generation. Liberalism is the program of naturalism. Free-thought begets free morals, or immorality. Restraint is thrown off and a free rein given to the passions. Whoever thinks what he pleases will do what he pleases. Liberalism in the intellectual order is license in the moral order. Disorder in the intellect begets disorder in the heart, and vice-versa. Thus does Liberalism propagate immorality, and immorality Liberalism.” .
Liberalism “is, therefore, the radical and universal denial of all divine truth and Christian dogma, the primal type of all heresy, and the supreme rebellion against the authority of God and His Church. As with Lucifer, its maxim is, ‘I will not serve.'” .
“Liberalism, whether in the doctrinal or practical order, is a sin. In the doctrinal order, it is heresy, and consequently a mortal sin against faith. In the practical order, it is a sin against the commandments of God and of the Church, for it virtually transgresses all commandments. To be more precise: in the doctrinal order, Liberalism strikes at the very foundations of faith; it is heresy radical and universal, because within it are comprehended all heresies. In the practical order it is a radical and universal infraction of the divine law, since it sanctions and authorizes all infractions of that law.”