In a unanimous decision authored by Justice Samuel Alito, the Supreme Court on Thursday upheld the right of an employee to be granted a religious accommodation by his employer unless doing so would substantially affect the employer’s business.

In Groff v. DeJoy, the high court reiterated that employees must not be forced to choose between their faith and their job, and finally clarified long-standing precedent that had been largely misunderstood and used to deny religious accommodations to employees for years.  

The petitioner in the case, Gerald Groff, had asked the justices to determine whether his employer, the U.S. Postal Service, was required to provide a religious accommodation excusing him from work so that he could observe the Sabbath on Sundays. 

Groff argued that he must, as Exodus 20:8 puts it, “[r]emember the Sabbath day, to keep it holy.”

When the Postal Service began delivering packages Sundays for Amazon, it initially accommodated Groff by exempting him from deliveries that day so that he could observe the Sabbath.

But a few years later, the Postal Service withdrew Groff’s religious accommodation and replaced it with an arrangement that regularly asked Groff to violate his conscience by working every Sunday when he could not find a replacement. Groff sued under Title VII of the Civil Rights Act of 1964, which prohibits employment discrimination “because of such individual’s race, color, religion, sex, or national origin.”

When a Pennsylvania federal trial court upheld the Postal Service’s decision not to accommodate Groff, he appealed to the U.S. Court of Appeals for the 3rd Circuit.  Although the 3rd Circuit agreed with Groff that the Postal Service had failed to provide him with a reasonable accommodation, it held that the Postal Service wasn’t required to do so because the accommodation would have caused “undue hardship” to the employer.

The problem? The 3rd Circuit had construed “undue hardship” to mean anything more than a “de minimis” (small or trivial) cost to the Postal Service.

So just how much hardship is actually “undue”? In answering that question, the Supreme Court wrestled with the contours of a decades-old case that had—it wrote—been largely misinterpreted.

In 1977, in Trans World Airlines Inc. v. Hardison, a case also centering on employee religious accommodations under Title VII, the Supreme Court wrote: “To require TWA to bear more than a de minimis cost in order to give Hardison Saturdays off is an undue hardship.” But this “de minimis” language doesn’t appear anywhere in Title VII.

Instead, subsection (j) of Title VII defines “religion” to include:

all aspects of religious observance and practice, as well as belief, unless an employer demonstrates that he is unable to reasonably accommodate to an employee’s … religious observance or practice without undue hardship on the conduct of the employer’s business.

In its new decision in Groff, the Supreme Court pointed out that when considering what amounted to “undue hardship” under Title VII, the court in Hardison had referred to both “de minimis” and “substantial” burdens.

That, wrote Alito, was because Hardison’s accommodation request had implicated the seniority rights of other employees granted by a collective bargaining agreement. Alito cited the Hardison opinion, noting that the essential question was whether Title VII “require[s] an employer and a union who have agreed on a seniority system to deprive senior employees of their seniority rights in order to accommodate a junior employee’s religious practices.”

Alito went on to explain:

Even though Hardison’s reference to ‘de minimis’ was undercut by conflicting language and was fleeting in comparison to its discussion of the ‘principal issue’ of [employee] seniority rights, lower courts have latched on to ‘de minimis’ as the governing standard … Hardison cannot be reduced to that one [‘de minimis’] phrase. In describing an employer’s ‘undue hardship defense, Hardison referred repeatedly to ‘substantial’ burdens, and that formulation better explains the decision.

The Supreme Court stated that Hardison should have been understood to say that, to satisfy the “undue hardship” standard under Title VII, an employer must demonstrate that it would result in “substantial increased costs in relation to the conduct of its particular business” before the employer may deny an employee’s request for a religious accommodation. 

The court concluded by holding that “Title VII requires that an employer reasonably accommodate an employee’s practice of religion, not merely that it assess the reasonableness of a particular possible accommodation or accommodations.”

Public Interest Law Firm First Liberty represented Groff throughout the case and celebrated its win.

“The court’s decision today restores religious freedom to every American in the workplace,” Kelly Shackelford, president, CEO, and chief counsel for First Liberty, said.

Aaron Street of Baker Botts, the attorney who argued Groff’s case before the justices, was exuberant in celebrating his client’s success, saying:

We are thrilled the court today recognized that an America that values religious pluralism should respect the religious liberty rights of every employee. Our nation has a long history of protecting its employees from being treated differently at work just because of their faith. This decision is consistent with that history and is a tremendous win for all people of faith.

In holding that a religious accommodation must be made to an employee unless the employer can demonstrate that doing so would result in substantially increased costs, the Supreme Court has provided welcome clarity and relief to religious employees across the country.

Thanks to the court’s unanimous decision, the scales of justice—once weighted heavily in favor of employers—now have been level-set.

Gerald Groff and millions of American workers just like him now may be confident that their religious beliefs and practices must be accommodated by their employers, unless it would truly constitute an “undue hardship.”

This piece originally appeared in The Daily Signal