This study argues that Felicite Lamennais (1782-1854) and Orestes Brownson (1803-1876) shared a similar vision for the temporal and spiritual separation between Church and State despite discordant historical perspectives and diametrically opposed political experiences. In the course of the nineteenth century, two 'public theologians' had the greatest impact and led the idealistic apology for the separation of Church and State. While Felicite Lamennais and Orestes Brownson maintained contrary perceptions of the Church and State; antithetical relationships with the Church; and, incompatible means of accomplishing their shared goal, both men embraced their Catholic tradition and political sensibility to advance a theological paradigm that encompassed their understanding of both the Church and State. Each looked upon the Church as the definitive revelation of God's invisible activity. Their quest for the fulfillment of the divine plan required the Church to influence the temporal State and the creation of a Catholic social order.
It was the congruous conclusion for each theologian that the Church, independent of State ascendancy, would form a positive, harmonious, and clearly visible synthesis of a revealed faith so as to form a unified moral order.