In its disregard of the Christian church and silence concerning Jesus Christ, the 1787 American Constitution was new in Christendom. Covenanters called the doctrine underlying political dissent the “mediatorial dominion of Christ” over the nations, meaning that the risen Christ–God and man in two distinct natures and one person forever–has full authority in heaven and on earth, including over nations and their governments. They should therefore recognize and submit to his rule. The lordship, or kingship, of Christ over all things is common to all Christians. Eighteenth-century Reformed Presbyterians added “mediatorial” to exclude the Scottish Associate Presbyterians (Seceders) teaching that Christ ruled over all things only as he was already God. In a long pamphlet war with the Seceders (nickname of the Associate Presbyterians), RPs argued that Seceder teaching amounted to a heretical denial of the hypostatic union of Christ’s divine and human nature. Associate Presbyterians followed some seventeenth-century Covenanters who, for polemical reasons of that era, applied the term “mediatorial” to Christ’s saving work in the church, not to his person.

William J. Edgar, History of the Reformed Presbyterian Church of North America 1920-1980, 388-389.