Gerald Groff began working for the U.S. Postal Service (USPS) in 2012. In 2013, USPS contracted with Amazon to deliver packages, including on Sundays. Groff’s religious beliefs prohibit working on Sunday, and so postmaster initially exempted Groff from Sunday work. Later, because of a union agreement had gone into effect, Groff was required to work Sundays during the peak season. Groff transferred to another station but then that station also began Sunday Amazon deliveries. The postmaster offered to adjust Groff’s schedule to permit him to attend religious services on Sunday mornings and to report to work afterward. He later sought others to cover Groff’s Sunday shifts. When Groff did not work on scheduled Sundays on which he was scheduled, he was disciplined. Groff’s request for a transfer to a position that did not require Sunday work could not be honored because no such position was available. The postmaster continued searching for Sunday coverage and sometimes made Sunday deliveries himself. Groff’s refusal to report on Sundays led to resentment among his coworkers, one of whom filed a grievance. Groff received additional discipline, after which he resigned.

Groff filed a lawsuit in which he alleged religious discrimination under Title VII, disparate treatment, and failure to accommodate. The court found for USPS. Groff appealed, and the Third Circuit Court of Appeals affirmed the summary judgment for USPS. The court did find that USPS failed to provide Groff with a reasonable accommodation because the shift swaps USPS offered Groff did not eliminate the conflict between his religious practice and his work obligations, but the court also found that the accommodation Groff sought would cause an undue hardship on USPS.

Groff appealed the Third Circuit decision to the U.S. Supreme Court. On writ of certiorari, the Center filed an amicus brief, arguing that the Third Circuit erred when it relied on TWA v. Hardison to find that the USPS was not required to provide Groff a reasonable accommodation to observe the Sabbath because doing so would have caused an undue hardship. The brief asks the Court to grant review of Groff’s case and overrule Hardison. The Supreme Court granted the cert. petition, agreeing to hear the case. The Center then filed a merits briefs in support of Groff. In addition to legal arguments about “undue hardship,” the brief’s distinctive feature is a tabulation of lower court accommodation cases involving summary judgment and which faiths they involved, thus showing the disproportionate importance of the accommodation provision to minority faiths.

On June 29, 2023, the Supreme Court found in favor of Groff. In a unanimous decision, the Court held that under Title VII an employer that denies an employee a religious accommodation “must show that the burden of granting an accommodation would result in substantial increased costs in relation to the conduct of its particular business.” In doing so, the Court explained that the interpretation of “undue hardship” by lower courts after Trans World Airlines, Inc. v. Hardison, 432 U.S. 63 (1977) to mean “any cost or effort that is ‘more than … de minimus’” is “a mistake.”