Religious accommodations are exemptions from compliance with the law. Before granting a religious accommodation, it would seem necessary to inquire about precisely how the law interferes with a claimant's system of religious belief and practice. And yet one of the most vexing issues in the law of religious accommodation concerns not merely the nature of a "substantial burden" on religious exercise, but even the propriety of any legal inquiry about religious burdens at all. Any assessment of the importance or centrality of a religious belief or practice within the claimant's belief system is strictly forbidden: "Repeatedly and in many different contexts, we have warned that courts must not presume to de- termine the place of a particular belief in a religion or the plausibility of a religious claim."'
There are two crucial reasons for deference to the claimant as to the quality of the burden. First, courts simply are not competent institutions to evaluate religious beliefs and practices. As the Supreme Court put it in United States v. Lee and Thomas v. Review Board: "It is not within 'the judicial function and judicial competence,' however, to determine whether appellee or the Government has the proper interpretation of the Amish faith; '[c]ourts are not arbiters of scriptural interpretation."' The argument from "incompetence" suggests precisely that courts are poor judges of what religion may require. Second, courts should defer not merely because they are poor judges of religion or are likely to make mistakes, but because even if they were good judges of religion they would risk excessively entangling church and state with too searching an inquiry. That is, their inquiries might trigger anti-establishment concerns. Thus, the Court has said that the First Amendment prohibits civil courts from interpreting "particular church doctrines" or opining on the "importance of those doctrines to the religion."' The Court's understandable reticence to tell Hobby Lobby that it was wrong about its own beliefs, or that its beliefs were "flawed," clearly suggests a reluctance to deal with issues that might entangle it in "religious and philosophical question[s]" or "draw [it] into impermissible questions of theology."'
The law of religious accommodation therefore puts courts in a bind. On the one hand, courts are required independently to evaluate, not only whether a burden on religion exists, but also whether that burden crosses what one might be forgiven for suspecting is an intentionally imprecisely defined threshold of substantiality. On the other hand, courts are required not to evaluate independently the burden or its substantiality for reasons of institutional incompetence and anti-entanglement, but instead to defer, and to defer completely, to the claimant. The more rigorously or abjectly courts defer, the less coherent the legal inquiry they are undertaking becomes; so much so that courts may lose sight of what they were supposed to be inquiring into in the first place.
Marc O. DeGirolami, Substantial Burdens Imply Central Beliefs, 2016 U. ILL. L. REV. ONLINE 19.