A school district cannot sponsor prayer at graduation – spoken or sung. Should a student speaker spontaneously pray, without any prior knowledge by school officials, it is not considered school sponsored. However, the district has an affirmative obligation to inform all speakers that prayer at a public school graduation is not legal. If, given the district’s prior knowledge of the speaker, it is not unreasonable to assume that the speaker may offer a prayer; the district has an affirmative obligation to pre-screen the content of the planned speech.