A three prong test first announced by the Supreme Court in Lemon v. Kurtzman, 403 U.S. 602, 29 L. Ed. 2d 745, 91 S. Ct. 2105 (1971), is usually used to assess whether government action violates the Establishment Clause. See, e.g., Mueller v. Allen, 463 U.S. 388, 394, 77 L. Ed. 2d 721, 103 S. Ct. 3062 (1983) (stating that "the general nature of our inquiry in this area has been guided, since the decision in Lemon v. Kurtzman, supra, by the 'three-part' test laid down in that case"); Barghout v. Bureau of Kosher Meat and Food Control, 66 F.3d 1337, 1341 (4th Cir. 1995) (applying Lemon). To pass the Lemon test, a government enactment must first "have a secular legislative purpose; second, its principal or primary effect must be one that neither advances nor inhibits religion; [and] finally, the statute must not foster, 'an excessive government entanglement with religion.'" Lemon, 403 U.S. at 612-13 (internal citations omitted).

As a practical matter, a per se rule focusing on coercion is a permissible substitute for the traditional Lemon test in this context because the mere fact that coercion is exerted by the state is enough to fail the second prong of the test. The second prong of Lemon (whether the primary effect is advancing or inhibiting religion) is interpreted and applied to forbid "at the very least, legislation that constitutes an endorsement of one or another set of religious beliefs or of religion generally." Barghout, 66 F.3d at 1345 (quoting Texas Monthly, Inc. v. Bullock, 489 U.S. 1, 8, 103 L. Ed. 2d 1, 109 S. Ct. 890 (1989)). In other words, "the government must appear neutral in matters of religious significance." Id. (citing Grumet, 512 U.S. at 696; Roemer v. Maryland Pub. Works of Maryland, 426 U.S. 736, 747, 49 L. Ed. 2d 179, 96 S. Ct. 2337 (1976)).

Example:  Sloan v. Powhatan County School Board