Charles Pinckney of South Carolina, who may have offered a similar provision as part of a package of proposals that he presented to the Convention about 10 days earlier (Farrand 1937, II, 342), proposed the prohibition on religious tests on August 30 (II, 468). At the time, the delegates were discussing the provision that would also appear in Article VI requiring all state and national officials to affirm their support of the U.S. Constitution. Gouverneur Morris of Pennsylvania joined in supporting Pinckney's motion to prohibit religious tests. Connecticut's Roger Sherman did not think that a constitutional prohibition was needed. He argued that "the prevailing liberality" was a "sufficient security agst. such tests" (II, 468). Rather than take the chance that such liberality would continue to prevail, the Convention unanimously voted to add the prohibition.
Apparently, some members remained unconvinced that the clause was a good idea. Maryland's Luther Martin later observed in a report of November 29 to the Maryland state legislature that
The proceedings of the Constitutional Convention were secret. Curiously, Jonas Phillips, a Jewish leader in Philadelphia, had sent a letter to George Washington, who was widely known for his liberal views toward religious liberty (Boller 1960), on September 2, just four days after the adoption of the prohibition on religious tests, in which he urged the Convention to reject them. He observed that existing state requirements requiring individuals to acknowledge the inspiration of the Old and New Testaments violated the beliefs of Jews, many of whom, like himself, had bravely fought during the Revolutionary War (St. John 1987, 194).
there were some members so unfashionable as to think, that a belief in the existence of a Deity, and of a state of future rewards and punishments would be some security for the good conduct of our rulers, and that, in a Christian country, it would be at least decent to hold out some distinction between the professors of Christianity and downright infidelity or paganism. (III, 227, italics omitted)
Many state constitutions subsequently copied the prohibition against religious oaths in the U.S. Constitution (Dreisbach, 272). The provision, which may have largely grown out of the inability to formulate a test that would apply to all of the colonies with their diverse denominations, did not of its own force invalidate existing state religious oaths. The adoption of the clause did help calm fears of a national religious establishment that opponents sometimes raised against the Constitution during ratification debates. A student of the subject observes that
Despite subsequent interpretations that have sometimes been placed on the clause in light of the religious clauses later included in the First Amendment, such delegates, like those at the Constitutional Convention, generally appear to have been more interested in using the clause to preserve
many delegates to the state conventions were unwilling to grant the new national regime authority to implement a practice (i.e., religious tests) that was common at the state level precisely because they wanted to retain the state tests and they feared a federal test might displace existing state tests. (Dreisbach, 286)
Boller, Paul F. 1960. "George Washington and Religious Liberty." William and Mary Quarterly, 3rd ser. 17 (October): 486–506. Bradley, Gerald V. 1987. "The Individual Liberties within the Body of the Constitution: A Symposium: The No Religious Test Clause and the Constitution of Religious Liberty: A Machine That Has Gone of Itself." Case Western Reserve Law Review 37: 674–747. Dreisbach, Daniel L. 1999. "The Constitution's Forgotten Religion Clause: Reflections on the Article VI Religious Test Ban." Journal of Church and State 38 (Spring): 261–296. Farrand, Max, ed. 1937. The Records of the Federal Convention. 4 vols. New Haven, CT: Yale University Press. Kurland, Philip B., and Ralph Lerner, eds. 1987. The Founders' Constitution. Vol. 4: Article 2, Section 2, through Article 7. Chicago: University of Chicago Press. St. John, Jeffrey. 1987. Constitutional Journal: A Correspondent's Report from the Convention of 1787. Ottawa, IL: Jameson Books.