Prior to oral argument in Hobby Lobby, Mark Gedicks argued that crafting an exemption for Hobby Lobby would itself amount to a violation of the Establishment Clause. The Solicitor General even added this argument in its brief. I commented here and here. This argument made a brief appearance in Justice Ginsburg’s dissent:

As the Court made clear in Cutter, the government’s license to grant religion-based exemptions from generally applicable laws is constrained by the Establishment Clause. 544 U. S., at 720–722. “[W]e are a cosmopolitan nation made up of people of almost every conceiva- ble religious preference,” Braunfeld, 366 U. S., at 606, a “rich mosaic of religious faiths,” Town of Greece v. Galloway, 572 U. S. ___, ___ (2014) (KAGAN, J., dissenting) (slip op., at 15). Consequently, one person’s right to free exercise must be kept in harmony with the rights of her fellow citizens, and “some religious practices [must] yield to the com- mon good.” United States v. Lee, 455 U. S. 252, 259 (1982).

The opinion closed with another reference to the Establishment Clause, but without endorsing (no pun intended) a position on this front:

There is an overriding interest, I believe, in keeping the courts “out of the business of evaluating the relative mer- its of differing religious claims,” Lee, 455 U. S., at 263, n. 2 (Stevens, J., concurring in judgment), or the sincerity with which an asserted religious belief is held. Indeed, approv- ing some religious claims while deeming others unworthy of accommodation could be “perceived as favoring one religion over another,” the very “risk the Establishment Clause was designed to preclude.” Ibid. The Court, I fear,has ventured into a minefield, cf. Spencer v. World Vision, Inc., 633 F. 3d 723, 730 (CA9 2010) (O’Scannlain, J., con- curring), by its immoderate reading of RFRA. I would confine religious exemptions under that Act to organiza- tions formed “for a religious purpose,” “engage[d] primarily in carrying out that religious purpose,” and not “engaged . . . substantially in the exchange of goods or services for money beyond nominal amounts.” See id., at 748 (Klein- feld, J., concurring).