The establishment clause prevents the government from creating a church, endorsing religion in general, or favoring one set of religious beliefs over another. As the Supreme Court decided in 1947 in Everson v. Board of Education of Ewing Township, the establishment clause was intended to erect “a wall of separation between church and state,” although the degree to which government should accommodate religion in public life has been debated in numerous Supreme Court decisions since then.
www.justicelearning.org, The United States Constitution, what it says, what it means, A Hip Pocket Guide (Oxford University Press)