Say you're working for a private employer, and you have a religious objection to a religion-neutral work rule: You might feel a religious obligation not to work Friday sundown to Saturday down, while the employer may require you to Saturdays or Friday nights. You might feel a religious obligation to wear a beard or a turban or a yarmulke or a headscarf, which may conflict with an employer dress and grooming code banning headgear or facial hair. You might feel a religious obligation not to get vaccinated, which may conflict with an employer requirement of vaccination.
One can debate on libertarian, egalitarian, or utilitarian grounds whether employers should have to give you an exemption from such rules. But in 1972, Congress said, as a matter of federal law, that they must indeed do so, unless they show that they're "unable to reasonably accommodate to an employee's … religious observance or practice without undue hardship on the conduct of the … business." How high a bar, though, should "undue hardship" be?
In TWA v. Hardison (1977), the Supreme Court held that "To require [an employer] to bear more than a de minimis cost in order to [accommodate the employee] is an undue hardship." The two most liberal members of the Court, Justices Marshall and Brennan objected, reasoning (among other things),
