a. No official church: Neither a state nor the federal government may set up an official church.
b. No coercion: Government may not “force [or] influence a person to go to or to remain away from church against his will or force him to profess a belief or disbelief in any religion.”
c. Punishment for beliefs: No one may be “punished for entertaining or professing religious beliefs or disbeliefs, for church attendance or non-attendance.”
d. No preference: Government may not prefer one religion over another. Also, government may not prefer religion to non-religion.
e. Participation: Government may not participate in the affairs of religious organizations, and such organizations may not participate in the affairs of government.
Note: Some of these prohibitions (e.g., the right not to be punished for one’s religious beliefs) are also protected by the Free Exercise Clause, perhaps even more directly than by the Establishment Clause. Nonetheless, the Everson Court purported to be listing solely those prohibitions stemming from the Establishment Clause.
2. Three-part test: The modern Court applies a three-fold test to determine whether governmental action violates the Establishment Clause. See Lemon v. Kurtzman, 403 U.S. 602 (1970). Only if the action satisfies each of the following conditions will it be valid:
b. Effect: Its principal or primary effect must neither advance nor inhibit religion; and
c. Entanglement: It must not foster an excessive government entanglement with religion.
d. Political division: Also, the law must not create an excessive degree of political division along religious lines. (However, this seems to be simply an aspect of the requirement of no “excessive entanglement”). See N&R, p. 1262.
3. Possible single “endorsement of religion” standard: There are some hints that the present Court may be unhappy with this Lemon three-part test, and that the Court may be moving to a single test: Does the state’s conduct amount to an “endorsement of religion”? See, e.g., Texas Monthly, Inc. v. Bullock, 489 U.S. 1 (1989), where the majority stated the main test as being whether the legislation “constitutes an endorsement of one or another set of religious beliefs or of religion generally.”