(a) At least four considerations show that retaining established, religiously expressive monuments, symbols, and practices is quite different from erecting or adopting new ones. First, these cases often concern monuments, symbols, or practices that were first established long ago, and thus, identifying their original purpose or purposes may be especially difficult. See Salazar v. Buono, 559 U.S. 700, 130 S.Ct. 1803, 176 L.Ed.2d 634. Second, as time goes by, the purposes associated with an established monument, symbol, or practice often multiply, as in the Ten Commandments monuments addressed in Van Orden and McCreary County v. American Civil Liberties Union of Ky., 545 U.S. 844, 125 S.Ct. 2722, 162 L.Ed.2d 729. Even if the monument’s original purpose was infused with religion, the passage of time may obscure that sentiment and the monument may be retained for the sake of its historical significance or its place in a common cultural heritage. Third, the message of a monument, symbol, or practice may evolve, Pleasant Grove City v. Summum, 555 U.S. 460, 477, 129 S.Ct. 1125, 172 L.Ed.2d 853, as is the case with a city name like Bethlehem, Pennsylvania; Arizona’s motto “Ditat Deus” (“God enriches”), adopted in 1864; or Maryland’s flag, which has included two crosses since 1904. Familiarity itself can become a reason for preservation. Fourth, when time’s passage imbues a religiously expressive monument, symbol, or practice with this kind of familiarity and historical significance, removing it may no longer appear neutral, especially to the local community. The passage of time thus gives rise to a strong presumption of constitutionality. Pp. 2080 – 2085.