[G]overnment endorsement . . . of religion . . . 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.
Sandra Day O'ConnorCommitment to the rule of law provides a basic assurance that people can know what to expect whether what they do is popular or unpopular at the time.
Sandra Day O'Connor