This chapter investigates the two non-establishment clauses in the U.S. Constitution: the no-religious-test clause in Article VI, and the no-establishment-of-religion clause in the First Amendment. Since religious tests were the clearest manifestation of state sovereignty over religion, their prohibition in Article VI elided any notion of a “Church of the United States” even before the First Amendment. The federal oath-Congress’s first act-no longer required a denial of Catholic beliefs as previous oaths had, yet loyalty remained a prerequisite to securing religious liberty. The chapter then contends that the First Amendment establishment clause was based on what Congress had stated in 1783: that powers in “purely spiritual” matters were “reserved to the several States, individually.” Congress had declared this principle in response to the Holy See’s request for it to approve a Catholic bishop, and had thus renounced one of the rights of patronage that governments traditionally held over ecclesiastical affairs. This context adds to the original meaning of the establishment clause, for simply prohibiting a national church did not necessarily forbid this right of patronage.

This chapter introduces the major philosophical concepts, historical interpretations, and political, legal, and economic issues concerning the First Amendment, church-state relations, and religious liberty in the United States. It will address philosophical concepts such as natural religion, the nature of religious exercise, and the special status of religious liberty in the philosophy of law. It will then present historical developments from colonial America to modern Supreme Court cases concerning church establishments, religious toleration, religious dissent and minorities, religious tests, and the historical and jurisprudential meanings of “free exercise” and “establishment.” It will conclude with reflections on natural rights and religious liberty exemptions, originalist constitutional interpretations, corporate religious liberty, the economic origins of religious liberty, the separation of church and state, and contemporary challenges to religious liberty.