This chapter explores how Pius XI’s social encyclical Quadragesimo anno – “On the Reconstruction of the Social Order”– not only reiterated Leo XIII’s condemnation of socialism and his critique of aspects of capitalism, but also outlined a program for Catholics to follow in order to address the social and economic upheavals of the time in a lasting and far-reaching manner. It also analyzes the two primary contributions of Quadragesimo anno to Catholic social doctrine. The first concerns Pius XI’s articulation of two principles of Catholic social teaching: subsidiarity and social justice. The second contribution is the encyclical’s articulation of a very substantial prescription for fundamental social change. While the developments at the level of principle introduced by Quadragesimo anno have proved lasting and become a set fixture of Catholic social doctrine, we observe how the particular proposals associated by Pius XI with these principles– most notably, the development of vocational groups and the establishment of a type of corporatist social order– had, by the time of Saint John XXIII, been considerably relativized by the magisterium.

This chapter is an analytical summary of Rerum novarum. Its goal is to illuminate the purpose of the encyclical and the main lines of Pope Leo’s reasoning, his key premises and central ethical conclusions, and in this way, to articulate as clearly as possible the teaching that comprises Rerum novarum. Rerum’s influence on Catholic teaching and practice is most manifest in the Church’s “social teaching,” which in various ways identifies the encyclical as its founding statement. This identification is made in the names and citations of some of the most important papal contributions to Catholic Social Teaching (CST) and is pervasive throughout the corpus of CST. And it is revealed in the ways in which the accepted principles of CST are present or anticipated in Rerum novarum. Although the chapter does not undertake the large and formidable task of characterizing CST, it does indicate how these principles figure in Pope Leo’s analysis. It also underlines the extent to which these principles are not the main point of Rerum novarum, but stand in the service of the moral and religious reform urged by Pope Leo.