On April 25, 1947, Edwin H. Rian renounced the jurisdiction of the Presbytery of Philadelphia of the Orthodox Presbyterian Church. On June 11 of that year he was re-ordained by the Presbytery of Philadelphia of the Presbyterian Church in the USA.
Rian had joined the OPC in 1936 as a constituting member at its first General Assembly. His 1940 book, The Presbyterian Conflict, defended the formation of the OPC. By 1947, however, Rian was frustrated over failures of the church to become more culturally engaged and particularly over the failure of efforts to form a Christian University. When he rejoined the PCUSA, Rian claimed that his study of Calvin's doctrine of the church persuaded him that the cause to which he was committed was sectarian. Its "self-righteousness," "intolerance," and "rigidity of doctrine" prompted a fight within the church over "non-essentials." His reassessment of the mainline church was a dramatic shift from his previous claim that it was "apostate" and contained ministers who "deny the very essentials of the faith." Moreover, in leaving the OPC he departed a church which he had characterized in this way in the Presbyterian Conflict:
In the formation of the Orthodox Presbyterian Church, Calvinism was given a new impetus in America. The spiritual heritage of Reformed teaching which had been stifled in the Presbyterian Church in the USA received a welcome in this church body, and the great doctrines of the Reformation, such as the sovereignty of God and salvation by grace alone, came to life again. Upon this high biblical ground the Orthodox Presbyterian Church stands, convinced that God will be pleased to use her to his glory and to the advancement of his kingdom.
- John Muether