Separation of church and state

The phrase "separation of church and state" describes the idea that government should not control religion or favor one faith and that religious bodies should not run government. It does not appear in the Constitution; it comes from Thomas Jefferson's 1802 letter to the Danbury Baptists, which spoke of "a wall of separation between Church & State," and the Supreme Court cited it in Everson v. Board of Education (1947).

The legal basis is the First Amendment's Establishment Clause and Free Exercise Clause. Courts have applied it to issues such as school prayer, funding for religious schools, displays on public property and tax rules for churches, for instance the Johnson Amendment. More recent decisions have emphasized history and equal treatment of religious groups.

Its interpretation is much debated. Some read it as a strict wall that keeps religion out of public institutions; others, including many religious conservatives, see the principle as protecting religion from government interference and consider it compatible with public acknowledgment of faith and equal access to public programs. Critics of strict separation argue it has been used to marginalize religious believers; critics of accommodation fear it favors majority religions. The test used by courts has shifted from the lemon test.