 In 1985, the United States Supreme Court ruled in ACLU v. Scarsdale, New York that nativity scenes on public lands violate separation of church and state statutes unless they comply with "The Reindeer Rule" — a regulation calling for equal opportunity for non-religious symbols, such as reindeer. This principle was further clarified in 1989, when the Supreme Court in County of Allegheny v. ACLU ruled that a crèche placed on the grand staircase of the Allegheny County Courthouse in Pittsburgh, PA violated the Establishment Clause, because the "principal or primary effect" of the display was to advance religion.
