The Supreme Court broadened protections on Thursday for religious workers in a case that involved a mail carrier for the U.S. Postal Service who refused to work on his Sabbath.
In a unanimous decision, the justices rejected a test that had long been used to determine what accommodations an employer must make for religious workers, but declined to rule on the merits of the case, sending it back to a lower court to consider under a new standard.
Writing for the court, Justice Samuel A. Alito Jr. said that the case gave it the “first opportunity in nearly 50 years” to explain the nuances of how workplaces must adapt to religious requests by employees.
For an employer to deny an employee’s request or a religious accommodation, Justice Alito wrote, it “must show that the burden of granting an accommodation would result in substantial increased costs in relation to the conduct of its particular business.”
The decision could affect countless workplaces and could require many employers to make substantial changes to accommodate religious workers.
The ruling is the latest in a series by the court that have focused on expanding the role of religion in public life, sometimes at the expense of other values, like gay rights and access to contraception.
In the past few years, the Supreme Court has ruled that a high school football coach had a constitutional right to pray at the 50-yard line after his team’s games, that state programs supporting private schools in Maine and Montana must include religious ones, that a Catholic social services agency in Philadelphia could defy city rules and refuse to work with same-sex couples who apply to take in foster children and that the Trump administration could allow employers with religious objections to deny contraception coverage to female workers.
The latest decision may be less divisive than some of the court’s recent rulings on religion, in part because protecting observance of the Sabbath may not split Americans along the usual lines. Indeed, liberal justices have tried in the past to shield workers from discipline and termination for following their faith, and all three on the court signed onto the decision.
The case was brought by Gerald Groff, an evangelical Christian and former missionary who worked as a substitute mail carrier. After the Postal Service made a deal with Amazon in 2013 to deliver packages on Sundays, Mr. Groff said he had to choose between his faith and his livelihood, opting to quit after being disciplined for missing work.
“I felt that I had a decision between what the post office wanted and what God wanted of me,” Mr. Groff said in an interview on Thursday. “I hope that this is inspiring to people because in America we do have these freedoms and they’re protected.”
The Postal Service said in a statement that it was confident that it would prevail once the lower court reconsidered the case.
Mr. Groff was represented by First Liberty Institute, which describes itself as the largest legal organization in the nation focused exclusively on defending religious freedom.
Kelly Shackelford, the president and chief counsel of First Liberty, welcomed the ruling, saying that it restored “religious freedom to every American in the workplace.”
“This decision will positively help millions and millions of Americans — those who work now and their children and grandchildren,” he said.
American Atheists, which advocates secularism in governmental policies and which submitted an amicus brief in support of the Postal Service in the case, Groff v. DeJoy, No. 22-174, said the ruling continued a worrying trend.
“While today’s decision doesn’t give religious employees carte blanche in the workplace, it certainly continues this court’s recent practice of expanding loopholes, accommodations and ‘rights’ for the religious while shifting more burdens onto atheists, humanists and the nonreligious,” said Geoffrey T. Blackwell, litigation counsel for the group.
Mr. Groff had sued under Title VII of the Civil Rights Act of 1964, a federal law that requires employers to “reasonably accommodate” workers’ religious practice so long as they can do so “without undue hardship” to the company’s business.
A 1977 precedent, Trans World Airlines v. Hardison, stood in his way. That decision said that employers need not accommodate workers if the effort imposed more than a trifling, or “de minimis,” burden on their businesses.
Lawyers for the Postal Service argued that Mr. Groff’s refusal to work on Sundays imposed a significant burden on a small post office, was in tension with an agreement with a labor union and was bad for other workers’ morale.
Lower courts ruled against Mr. Groff. Judge Patty Shwartz, writing for a divided three-judge panel of the U.S. Court of Appeals for the Third Circuit, in Philadelphia, said that “exempting Groff from working on Sundays caused more than a de minimis cost on U.S.P.S. because it actually imposed on his co-workers, disrupted the workplace and work flow, and diminished employee morale.”
In dissent, Judge Thomas M. Hardiman wrote that “the majority renders any burden on employees sufficient to establish undue hardship, effectively subjecting Title VII religious accommodation to a heckler’s veto by disgruntled employees.”