The separation of church and state and the protection of religious freedom are important cornerstones of American constitutional law. Over the last two hundred years, the Supreme Court has generally sided with religious institutions in First Amendment cases. And in some cases, traditions that began as religious became seen as secular - and therefore constitutional.
What the First Amendment Says
"Congress shall make no law respecting an establishment of religion, or prohibiting the free exercise thereof..."
What Are Sunday Closing Laws?
United States Library of Congress, The Constitution of the United States of America: Analysis and Interpretation
The history of Sunday Closing Laws goes back into United States colonial history and far back into English history.1 Commonly, the laws require the observance of the Christian Sabbath as a day of rest, although in recent years they have tended to become honeycombed with exceptions.
The Supreme Court rejected an Establishment Clause challenge to Sunday Closing Laws in McGowan v. Maryland.2 The Court acknowledged that historically the laws had a religious motivation and were designed to effectuate concepts of Christian theology. However, in light of the evolution of our Sunday Closing Laws through the centuries, and of their more or less recent emphasis upon secular considerations, it is not difficult to discern that as presently written and administered, most of them, at least, are of a secular rather than of a religious character, and that presently they bear no relationship to establishment of religion.3
The fact that this [prescribed day of rest] is Sunday, a day of particular significance for the dominant Christian sects, does not bar the State from achieving its secular goals. To say that the States cannot prescribe Sunday as a day of rest for these purposes solely because centuries ago such laws had their genesis in religion would give a constitutional interpretation of hostility to the public welfare rather than one of mere separation of church and State.4
The choice of Sunday as the day of rest, although originally religious, now reflected simple legislative inertia or recognition that Sunday was a traditional day for the choice.5 Valid secular reasons existed for not simply requiring one day of rest and leaving to each individual to choose the day, reasons of ease of enforcement and of assuring a common day in the community for rest and leisure.6 Later, a state statute mandating that employers honor the Sabbath day of the employee’s choice was held invalid as having the primary effect of promoting religion by weighing the employee’s Sabbath choice over all other interests.7
More on the Religion Clauses
1. The history is recited at length in the opinion of the Court in McGowan v. Maryland, 366 U.S. 420, 431–40 (1961), and in Justice Frankfurter’s concurrence. Id. at 459, 470–551 and appendix.
2. 366 U.S. 420 (1961). Decision on the establishment question in this case also controlled the similar decision on that question in Two Guys from Harrison-Allentown v. McGinley, 366 U.S. 582 (1961), Braunfeld v. Brown, 366 U.S. 599 (1961), and Gallagher v. Crown Kosher Super Market, 366 U.S. 617 (1961). On free exercise in Sunday Closing cases, see Free Exercise Exemption From General Governmental Requirements, infra.
3. McGowan v. Maryland, 366 U.S. 420, 444 (1961).
4. 366 U.S. at 445.
5. 366 U.S. at 449–52.
6. 366 U.S. at 449–52. Justice Frankfurter, with whom Justice Harlan concurred, arrived at the same conclusions by a route that did not require approval of Everson v. Board of Education, from which he had dissented.
7. Estate of Thornton v. Caldor, Inc., 472 U.S. 703 (1985).