Opinion of the Court
worldly “goods.” App. 294. In 2012, Groff began his employment with the United States Postal Service (USPS), which has more than 600,000 employees. He became a Rural Carrier Associate, a job that required him to assist regular carriers in the delivery of mail. When he took the position, it generally did not involve Sunday work. But within a few years, that changed. In 2013, USPS entered into an agreement with Amazon to begin facilitating Sunday deliveries, and in 2016, USPS signed a memorandum of understanding with the relevant union (the National Rural Letter Carriers’ Association) that set out how Sunday and holiday parcel delivery would be handled. During a 2-month peak season, each post office would use its own staff to deliver packages. At all other times, Sunday and holiday deliveries would be carried out by employees (including Rural Carrier Associates like Groff) working from a “regional hub.” For Quarryville, Pennsylvania, where Groff was originally stationed, the regional hub was the Lancaster Annex.
The memorandum specifies the order in which USPS employees are to be called on for Sunday work outside the peak season. First in line are each hub’s “Assistant Rural Carriers”—part-time employees who are assigned to the hub and cover only Sundays and holidays. Second are any volunteers from the geographic area, who are assigned on a rotating basis. And third are all other carriers, who are compelled to do the work on a rotating basis. Groff fell into this third category, and after the memorandum of understanding was adopted, he was told that he would be required to work on Sunday. He then sought and received a transfer to Holtwood, a small rural USPS station that had only seven employees and that, at the time, did not make Sunday deliveries. But in March 2017, Amazon deliveries began there as well.
With Groff unwilling to work on Sundays, USPS made other arrangements. During the peak season, Sunday deliveries that would have otherwise been performed by Groff
