Separation of Church and State Definition

A phrase crafted by Thomas Jefferson in response to the Danbury Baptist Association, intended to describe his view of the proper relationship between organized religion and the government. From time to time, the phrase has appeared in court decisions interpreting the First Amendment religion clauses, and especially the establishment clause.

For example, in Everson v. Board of Education, 330 U.S. 1, 16 (1947), Justice Black quoted the phrase while explaining that the government cannot participate in the affairs of a religious group, set up a church, aid or prefer one religion over another, or aid or prefer religion over nonreligion.