Everson v Board of Education - It Begins...

Supreme Court, 1947, Everson vs Board of Education (banning prayer in public schools): the court said that the "establishment clause" applied equally to the states as to the federal government. The amendment says "Congress shall make no law..." but the court said the 14th amendment makes the establishment clause apply to the states. The 14th says: "no state shall deprive any person of life, liberty, or property without due process of law." The court said freedom here also refers to religious freedom, so no state may make any law establishing religion. Hugo Black wrote the opinion in that case and for the first time in American jurisprudence, introduced the phrase "separation of church and state," found in a letter written by Thomas Jefferson. He also said that America was a secular nation (the first time that had been stated officially, also), despite previous Supreme Court decisions that indicated America was a Christian nation. The Supreme Court in this case had no court precedents or previous court decisions to cite; this was never before part of American jurisprudence; the concept was not in previous decisions and is not in the Constitution. Black also implied in this decision that the establishment clause could be upheld without considering the freedom of religion clause.

Learn more from The Constitution & Religion : Leading Supreme Court Cases on Church and State