In the 1962 case, Engle v. Vitale, the Supreme Court declared school sponsored prayer unconstitutional. Justice Hugo Black wrote: "constitutional prohibition against laws respecting an establishment of a religion must at least mean that it is no part of the business of the government to compose official prayers for any group of the American people to recite as part of a religious program carried out by government."
The Court has ruled in subsequent cases against the reading of the Bible in school. In 1981, the court overturned a Kentucky law requiring the posting of the Ten Commandments in school. It also overturned an Alabama law that authorized a minute of silence for voluntary prayer. The Court wrote that the state was not just allowing prayer, but was attempting to force it. It should be noted that nothing in what the court has written stops a group of students from getting together and praying. What it does do is make it clear that school cannot directly promote the prayer.