36 To the Encyclical of Leo, therefore, must be given this credit, that these associations of workers have so flourished everywhere that while, alas, still surpassed in numbers by socialist and communist organizations, they already embrace a vast multitude of workers and are able, within the confines of each nation as well as in wider assemblies, to maintain vigorously the rights and legitimate demands of Catholic workers and insist also on the salutary Christian principles of society.
Source: Quadragesimo Anno (Vatican.va)