Separationism, which is sometimes referred to as the separation of church and state, provided the dominant theme of Establishment Clause jurisprudence for almost 50 years. The basic premise of separationism is that religion and government do not mix well, each presenting dangers to the other. Everson v. Board of Educ., 330 U.S. 1, 9-16 (1947). In Everson, the Court relied heavily on the history of religious persecution and intolerance toward minority religions as support for the separationist thesis. From the perspective of this thesis, the Establishment Clause is sometimes described as creating a “wall of separation” between church and state—a metaphor borrowed from Thomas Jefferson.
The Court’s reliance on separationism has not, however, created an impregnable barrier between church and state. From a realistic perspective, some interaction between government and religion is inevitable, and the developed separationist jurisprudence recognizes that inevitability. Thus, parochial schools are surely entitled to police and fire protection even though such protection assists, at least indirectly, the sectarian mission of the school. Overall, however, the theme of separationism is to keep separate, as much as reasonably possible, the realms of church and state. See McCreary County v. ACLU, 545 U.S. 844 (2005) (applying separationist model); Lee v. Weisman, 505 U.S. 577, 609 (1992) (Souter, J., concurring) (defending the separationist model). As applied, this means that the government has no power to create an officially recognized church; to prefer one religion over another; to pass laws specifically designed to aid one religion or all religions; or to support, financially or otherwise, the teaching or practice of religion. Everson v. Board of Education, 330 U.S. at 15-16.
Nonpreferentialist theory, on the other hand, rejects the “wall of separation” metaphor and is premised instead on the idea that the government may provide aid to religion and religious institutions as long as the government does not favor or prefer any one religion or group of religions over others. Proponents of nonpreferentialism read the history of religious persecution and intolerance as indicative of a need to prevent discriminations between religions or religious sects, but not as requiring government to separate itself completely from the sphere of religion. They note that from the time of the First Congress—the Congress that proposed the First Amendment—the United States has promoted various religious activities, thus placing a gloss on the meaning of the Establishment Clause. For example, the First Congress through joint resolution created the Thanksgiving holiday as “a day of public thanksgiving and prayer, to be observed by acknowledging with grateful hearts the many and signal favors of Almighty God.” In short, according to proponents of nonpreferentialism, while the government may not discriminate between religions, it is free to promote religion in general. See McCreary County v. ACLU, 545 U.S. at 885 (Scalia, J., dissenting) (defending nonpreferential model); Wallace v. Jaffree, 472 U.S. 38, 91 (1985) (Rehnquist, J., dissenting) (same). In recent years, nonpreferentialist theory has become increasingly influential on the Court.