The First Amendment to the United States Constitution reads:
- "Congress shall make no law respecting an establishment of religion, or prohibiting the free exercise thereof; or abridging the freedom of speech, or of the press; or the right of the people peaceably to assemble, and to petition the Government for a redress of grievances."
The following summaries rely on Supreme Court decisions which have clarified and defined the meaning and scope of this amendment.
While the phrase "separation of church and state" does not appear in the First Amendment, the concept (originally mentioned by Thomas Jefferson) is a logical extension of the establishment and free exercise clauses. True freedom of religion depends on government neutrality with regard to religion.
- "Congress shall make no law respecting an establishment of religion"
This clause may appear to simply prevent the U.S. Congress from declaring a national religion. However, the Fourteenth Amendment extends these protections to all citizens, effectively prohibiting individual states from circumventing rights guaranteed by the U.S. Constitution. Additionally, the Supreme Court has determined that the scope of this clause implies that "Government should not prefer one religion to another, or religion to irreligion" (Justice David Souter, for the majority in Board of Education of Kiryas Joel Village School District v. Grumet).
Note that the word "respecting" in this clause means "regarding" and not "showing respect for".
Free exercise clause
- "...or prohibiting the free exercise thereof"
Essentially, the rights of each individual to exercise their religious beliefs cannot be infringed. The government can intervene and prohibit certain religious practices if they conflict with other laws and if such interference has a secular, religiously neutral purpose. Generally one individual's rights end where another's begin, ensuring that "free exercise" cannot be used as an excuse for violating the rights of others.
The Supreme Court has interpreted the establishment clause as meaning that the government may not favor one religion over another, or favor religion in general over no religion (or vice-versa). In other words, the government must remain strictly neutral in matters of religion.
At the same time, the free exercise clause guarantees freedom of religion. A proper balance between these two clauses can sometimes be hard to find.
Sherbert v. Verner, 1963
Sherbert v. Verner was significant in determining the way freedom of conscience is handled in the US. A Seventh-day Adventist was changed from a five day to a six day working week, including Saturday. Since they considered working on Saturday to be working on the Sabbath, she refused to work and was subsequently fired. She applied for unemployment benefit and was denied. The legal challenge progressed to the US Supreme court, while ruled that denying her belief was an "unconstitutional burden on the free exercise of her religion". The dissenting opinion pointed out this ignored potential secular beliefs such as Saturday (or any other day) should not be a day of work, which is either unfair or an absurd conclusion to reach.
- "The State, in other words, must single out for financial assistance those whose behavior is religiously motivated, even though it denies such assistance to others whose identical behavior (in this case, inability to work on Saturdays) is not religiously motivated. It has been suggested that such singling out of religious conduct for special treatment may violate the constitutional limitations on state action. [...] Those situations in which the Constitution may require special treatment on account of religion are, in my view, few and far between"
The court's ruling gave rise to the Sherbert test, which prevented any substantial burden on the exercise of religion unless there was suitable justification for such a burden. Some legal scholars argue that laws should apply equally and while religion should be be subject to discrimination, it should not be privileged either.
- "[Equal regard] holds that the interests and concerns of every member of the political community should be treated equally, that no person or group should be treated as unworthy or otherwise subordinated to an inferior status "
- "It is impossible to defend the privileging view of religious liberty in any way consistent with this requirement of impartiality [equal regard]; as a result, every theory that supposes religion to be constitutionally privileged will run afoul of basic norms associated with the Establishment Clause. "
- "[...] the promise of strict scrutiny review for religious exemption cases has remained largely unfulfilled. [...] many scholars and students alike interpret the Court's holdings as a preference for religion over secular forms of conscience. [... Regarding Sherbert and related cases,] The Court therefore appeared to be saying that religiously motivated conduct will be guarded against state intrusions animated by all but the most compelling of governmental interests. "
The weight to grant religious beliefs and exactly how to apply the principles of the US constitution, specifically the establishment clause of the 1st amendment, remain controversial to this day.
Lemon v. Kurtzman, 1971
- Main Article: Lemon test
In the 1971 case Lemon v. Kurtzman, the Supreme Court established the Lemon test for determining whether a law violates the establishment clause: a law is legal if: 
- It has a legitimate secular purpose, and
- Its principal effect neither advances nor inhibits religion, and
- It does not foster an excessive government entanglement with religion.
Employment Division v. Smith, 1990
- "The rule respondents favor would open the prospect of constitutionally required religious exemptions from civic obligations of almost every conceivable kind -- ranging from compulsory military service to the payment of taxes to health and safety regulation such as manslaughter and child neglect laws, compulsory vaccination laws, drug laws, and traffic laws; to social welfare legislation such as minimum wage laws, child labor laws, animal cruelty laws, environmental protection laws, and laws providing for equality of opportunity for the races. "
City of Boerne v. Flores, 1997
In 1997, the Supreme Court struck down part of Religious Freedom Restoration Act which prohibited states being able to legislate on land use. While this is relevant to the separation of church and state, the court struck down the act based on the 14th amendment. 
Gonzales v. O Centro Espirita Beneficente Uniao do Vegetal, 2006
Entheogen, the government failed show it had a "compelling interest"
- "Before this Court, the Government's central submission is that it has a compelling interest in the uniform application of the Controlled Substances Act, such that no exception to the ban on use of the hallucinogen can be made to accommodate the sect's sincere religious practice. We conclude that the Government has not carried the burden expressly placed on it by Congress in the Religious Freedom Restoration Act "
Town of Greece v. Galloway, 2013
- "The [US Supreme] Court must decide whether the town of Greece, New York, imposes an impermissible establishment of religion by opening its monthly board meetings with a prayer. It must be concluded … that no violation of the Constitution has been shown "
The Bible as an official state book
In 2015, the Tennessee house of representatives adopted the Bible as their official state book.
- "While some representatives argue the holy book’s importance to state history and culture, others say measure blatantly violates separation of church and state "
- ↑ 
- ↑ C. Eisgruber and L. Sager, Equal Regard in Law and Religion: A Critical Anthology, S. Feldman, ed.; New York: New York Univ. Press, 2001.
- ↑ Prabha Sipi Bhandari, The Failure of Equal Regard to Explain the Sherbert Quartet, NYU Law review, April 1997
- ↑ Lemon v. Kurtzman
- ↑ 
- ↑ 
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- ↑ Town of Greece Decision May Change How Supreme Court Looks at First Amendment
- ↑ 
- The Young Turks, Public School Fined For Proselytizing Christianity, 1 Aug 2015