appropriate circumstances be perfectly acceptable to Christians. Libertas Praestantissimum (1888) approved in the conditions of the modern world the liberal principles of democracy and tolerance. Rerum Novarum (1891) accepted the socialist principles of State intervention and class organisation. And Au Milieu des Solicitudes (1892) specifically warned Catholic leaders in France not to try to overturn but to work with the liberal Republic. Leo laid down the ground rules for Christian engagement in political life. In Immortale Dei (1885) he said this:
God, therefore, has appointed the charge of the human race between two powers, the ecclesiastical and the civil, the one being set over divine and the other over human things. Each in its kind is supreme ... One of the two has for its proximate and chief object the well-being of this mortal life; the other the everlasting joys of heaven. Whatever, therefore, in things human is of a sacred character, whatever belongs either of its own nature or by reason of the end to which it is referred, to the salvation of souls, or to the worship of God, is subject to the power and judgment of the Church. Whatever is to be ranged under the civil and political order is rightly subject to the civil authority. Jesus Christ has Himself ordered that what is Caesar's is to be rendered to Caesar, and what is God's to God.
Given this lead, many Catholics felt challenged to elevate Christian compassions for the poor and the weak into an engagement for actual social reform. They also began to urge the Church itself to be less socially conservative and authoritarian. They believed such engagement would provide a bulwark against corrosive materialism while lessening the impact of rapid economic changes upon traditional values and social cohesion. Fogarty warns against seeing Leo XIII's encyclicals as a flash of revealing light:
Rerum Novarum marked a turning point, it did not create one. Like all papal encyclicals, it represented the summing up of a certain stage of thought and discussion about social problems among Catholics, both clerical and lay. Rerum Novarum represented the turn of the screw which brought one part of the picture finally into focus.4