In the apostolic letter Notre Charge apostolique of August 25, 1910, which condemns the French Catholic leftist movement known as Le Sillon of Marc Sangnier, Saint Pius X analyzes the celebrated trilogy.
“The Sillon is nobly solicitous for human dignity; but it understands that dignity in the manner of certain philosophers of whom the Church does not at all feel proud. The first element of that dignity is liberty, understood in the sense that, except in the matter of religion, each man is autonomous. From this fundamental principle it draws the following conclusions: today the people are in tutelage under an authority distinct from themselves; they ought to free themselves from it: political emancipation. They are dependent upon employers who hold their instruments of labor, exploit them, oppress them and degrade them; they should shake off the yoke: economic emancipation. Finally, they are ruled by a caste, called the directing caste, to whom their intellectual development gives an undue preponderance in the direction of affairs; they must break away from this domination: intellectual emancipation. The leveling down of conditions from this triple point of view will establish equality amongst men, and this equality is true human justice. A political and social organization founded upon this double basis, liberty and equality (to which will soon be added fraternity)—this is what they call democracy….
Marc Sangnier, founder of Le Sillon
“First of all, in politics, the Sillon does not abolish authority; on the contrary, it considers it necessary; but it wishes to divide it, or rather to multiply it in such a way that each citizen will become a kind of king….
“Proportions being preserved, it will be the same in the economic 
order. Taken away from a particular class, the mastership will be so well multiplied that each workingman will become a sort of master….
“We come now to the principal element, the moral element….. Snatched away from the narrowness of private interests, and raised up to the interests of the profession, and, even higher, to those of the whole nation, nay, higher still, to those of humanity (for the horizon of the Sillon is not bounded by the frontiers of the country, it extends to all men, even to the ends of the earth), the human heart, enlarged by the love of the common welfare, would embrace all comrades of the same profession, all compatriots, all men. Here is human greatness and nobility, the idea realized by the celebrated trilogy, liberty, equality, fraternity….
“Such, in short, is the theory—we might say the dream—of the Sillon.”
In this manner, Saint Pius X continues in the footsteps of his predecessors who, since Pius VI, condemned the errors implied in the motto of the French Revolution.
Plinio Corrêa de Oliveira, Nobility and Analogous Traditional Elites in the Allocutions of Pius XII: A Theme Illuminating American Social History (York, Penn.: The American Society for the Defense of Tradition, Family, and Property, 1993), Appendix III, pp. 384-385.
