The justices took up Gerald Groff's case after lower courts dismissed his claim that the Postal Service violated federal anti-discrimination law by refusing to exempt him from working on Sundays, when he observes the Sabbath, finding that his demands placed too much hardship on his co-workers and employer.

The case gives the court, which has a 6-3 conservative majority, another opportunity to back a plaintiff who has made a claim of anti-religion discrimination.

(Reporting by Andrew Chung; Editing by Will Dunham)

By Andrew Chung