A government agency may legally lend geography books containing maps to religious day schools but may not lend maps alone or films on geography. It may bus students from their homes to such schools but not from the schools to museums. It may diagnose speech or hearing problems on the schools' premises, but subsequent therapy must occur elsewhere if public money is involved.
The U.S. Supreme Court has drawn some confusing borders between church and state, basing its decisions on a fervently disputed phrase in the Constitution: "Congress shall make no law respecting an establishment of religion." As interpreted by the...