Because of the prohibition of the First Amendment against the enactment of any law "respecting an establishment of religion," which is made applicable to the States by the Fourteenth Amendment, state officials may not compose an official state prayer and require that it be recited in the public schools of the State at the beginning of each school day -- even if the prayer is denominationally neutral and pupils who wish to do so may remain silent or be excused from the room while the prayer is being recited. Pp. 422-436.