O’Connor introduced her endorsement test in a concurring opinion in Lynch v. Donnelly (1984). The case involved a Christmas display in Pawtucket, Rhode Island, that featured a nativity scene alongside other more secular symbols, such as a Santa Clause, a reindeer, and as a holiday greeting banner.

The majority of the court, in an opinion by Chief Justice Warren Burger, applied the Lemon test to find the display permissible. O’Connor proposed what she termed a “clarification” of Lemon by applying an endorsement analysis. Justice O’Connor stated: “The second and more direct infringement is government endorsement or disapproval of religion. Endorsement sends a message to nonadherents that they are outsiders, not full members of the political community, and an accompanying message to adherents that they are insiders, favored members of the political community. Disapproval sends the opposite message.”