In Lemon v. Kurtzman, 403 U.S. 602 (1971), the Court created the Lemon Test. It does not bar religion in government; provided, the legislation has a secular legislative purpose, does not have the primary effect of either advancing or inhibiting religion, and must not result in an "excessive government entanglement" with religion.
Hein v. Freedom From Religion Foundation, 551 U.S. 587 (2007) held that the government can partner with religious organisations and can even give them tax payer dollars.
Lamb's Chapel v. Center Moriches Union Free School District, 508 U.S. 384 (1993) held that a government cannot deny a religious group accommodations that are opened to others nor can it prohibit the screening of religious films.
Newdow v. United States Congress, Elk Grove Unified School District, et al., 542 U.S. 1 (2004) held that the words "Under God" are not violative of the Constitution.
Aronow v. United States, 432 F.2d 242 (9th cir. 1970), Newdow v. United States Congress, 542 U.S. 1 (2004) have both rejected claims that "In God We Trust" violates the First Amendment.
Salazar v. Buono, 559 U.S. ___ (2010) held that crosses on public property are not unconstitutional.
Walz v. Tax Commission of the City of New York, 397 U.S. 664 (1970) upheld tax exempt status for religious institutions.
Edwards v. Aguillard, U.S. 578 "teaching a variety of scientific theories about the origins of humankind to school children is validly done with the clear secular intent of enhancing the effectiveness of science instruction."
Bradford v. Roberts, 175 U.S. 291 (1899), held that taxpayers had no grounds upon which to sue and that governmental funding to religious entities like hospitals is not unconstitutional.
Bowen v. Kendrick, 487 U.S. 589 (1988), the use of federal funds to do research into the subject of premarital adolescent sexuality does not violate the Establishment Clause. The funds were allowed to be given to religious organisations if they offered counseling services.
Marsh v. Chambers, 463 U.S. 783 (1983), the practice of beginning the legislative session with a prayer given by the publicly funded chaplain is constitutional.
Lynch v. Donnelly, 463 U.S. 783 (1983), governments can display Christmas symbols on the property of local non-profit organisation. The display included traditional items such as a tree, a Santa Claus, and a nativity scene. The display does not violate the Establishment Clause.
County of Allegheny v. ACLU Greater Pittsburgh Chapter, 492 U.S. 573 (1989), a government-owned menorah on display on public property does not violate the Establishment Clause.
Agostini v. Felton, 521 U.S. 203 (1997), public school teachers may instruct at religious schools, so long as the material was secular and neutral in nature and no "excessive entanglement" between government and religion was apparent. It does not violate the First Amendment.
Mitchell v. Helms, 121 s.Ct. 15 (2000), the Court ruled that the loans were permissible because they in no way represented a governmental indoctrination or advancement of religion. The loans were made in a nondiscriminatory and constitutional fashion to both secular and non-secular schools. "Whether governmental aid to religious schools results in religious indoctrination ultimately depends on whether any indoctrination that occurs could reasonably be attributed to governmental action." As the contents of the loans were appropriate for both religious and public schools the government was not serving to advance religion.
Pierce v. Society of Sisters of the Holy Names of Jesus and Mary, 268 U.S. 510 (1925), enforcement of the Compulsory Education Act, which would force parents to send their children to public schools, would lead to the destruction of the petitioners primary schools. These schools serve a valuable function in their communities. The Act unreasonably interferes with the liberty of parents and guardians to direct the upbringing and education of children under their control. In order to impose such limitations on the choices of parents, the state must be furthering a legitimate interest. Such is not the case in this instance as uniformity of children appears to be the only end served.
Zobrest v. Catalina Foothills School District, 509 U.S. 1 (1993), the Court required the school district to offer Zobrest the sign language interpreter to a student in a parochial school.
Meuller v. Allen, 463 U.S. 388 (1983), laws allowing parents to deduct from their state income taxes any expenses from school tuition, textbooks, or transportation for their children are not unconstitutional. This covered elementary and secondary students and was available regardless of whether the children attended public or private (including parochial) schools.
Committee for Public Education and Religious Liberty v. Regan, 444 U.S. 646 (1980), Court held constitutional a New York passed a statute allowing nonpublic schools to be reimbursed for the costs incurred in administering and reporting results of state-mandated test scores. The funds given to the schools were audited to ensure that the money was only used to cover the costs of compliance with the state standards. Law constitutional.
Wolman v. Walter, 433 U.S. 229 (1977), a state may provide textbooks, standardized tests, therapeutic and diagnostic services to private and parochial school children.
Roemer v. Maryland Public Works Board, 426 U.S. 736 (1976), a state may give tax dollars to parochial and private schools grants with the stipulation that the money only be spent on secular functions.
Meek v. Pittinger, 421 U.S. 395 (1975), governments can purchase school books for private and parochial schools.
Tilton v. Richardson, 403 U.S. 672 (1971), state grants to parochial and private schools are constitutional.
Hosanna-Tabor Evangelical Lutheran Church and School v. Equal Employment Opportunity Commission, the Establishment and Free Exercise Clauses of the First Amendment bar suits brought on behalf of ministers against their churches, claiming termination in violation of employment discrimination laws.