Illinois teachers unions Monday criticized a U.S. Supreme Court decision that ruled in favor of a Washington high school football coach who lost his job after he persisted in praying on the field despite objections from the school district. Legal experts said the ruling called into question decades of precedent that puts limits on religious expression in public schools.

Though the decision’s long-range impact is not yet clear, the ruling could open the door for more religion in public schools, according to legal experts, though they warned teachers and coaches against interpreting the opinion too broadly.

“I think what this case does is raise the concern that schools or particular teachers will feel emboldened to inject more religion into the classroom,” said Rebecca Glenberg, senior supervising attorney for the American Civil Liberties Union Illinois, “but I would urge them to be careful because … the Supreme Court’s other precedents with respect to prayer in school and religious coercion remain in effect.”

The nation’s high court handed down the 6-3 decision in Kennedy v. Bremerton School District days after it overturned Roe v. Wade, the landmark 1973 that protected the right to choose to have an abortion, further roiling a polarized country.

Legal experts, unions and advocates for removing religion from public schools cited alarm at the decision.

“It protects students far less from potentially atmospherically coercive pressures,” said Mary Anne Case, a professor of law at the University of Chicago. “It makes it that much harder for a student to feel and be safe being an outlier.”

Kathi Griffin, president of the Illinois Education Association, which represents more than 135,000 teachers and staff, said the Supreme Court decision “chips away at the rights of our students.”

“It leaves our students vulnerable to religious coercion in their public schools,” she said in a statement. “The decision gives privilege and protection to specific sectarian religious speech, instead of putting our students first.”

The Chicago Teachers Union referred to a statement from American Federation of Teachers President Randi Weingarten, who said that the “extremists on the Supreme Court one more time ignored the constitutional doctrine of separation of church and state.”

“As a union that represents educators who teach, coach and support millions of students every day, we believe that schools should be safe spaces for everyone,” she said.

The case was filed by Joseph Kennedy, an assistant football coach at a Seattle-area school whose contract was not renewed after he continued to pray after games at the 50-yard line despite being told not to by the school district in 2015. The incident caused a media storm and led to a lawsuit in which Kennedy argued his free speech rights were violated.

Lower courts mostly ruled in favor of the school district, which argued that Kennedy’s actions disregarded district policy meant to keep the schools from running afoul of the First Amendment’s establishment clause that prohibits government-imposed religious activity.

Tensions surrounding religious expression at sporting events have long flared up.

In 2015, Naperville Community Unit School District 203 banned team prayers at high school athletic events after a photo of players praying went public.

In 2017, the Vandalia School District apologized after a coach took part in a prayer circle with students after a game, according to the Freedom From Religion Foundation, a Wisconsin-based organization that acts as a watchdog for separation of church and state.

Despite Monday’s decision, legal experts cautioned teachers and coaches against incorporating prayer into school-based activities.

“It’s a very odd opinion because it works so hard to distort the underlying facts,” said Andy Koppelman, a professor of law at Northwestern University.

In the court’s majority opinion, Justice Neil Gorsuch writes, in a narrative disputed by the dissenting justices, that Kennedy lost his job because he “offered his prayers quietly while his students were otherwise occupied.” Gorsuch wrote that students were not coerced to join in the prayers.

“That raises at least some possibility that this decision, like many of the court’s earlier decisions, resolves this case without clearing up the law at all,” Koppelman said, noting that students who show they felt pressure to participate in religious activity could still prevail under this ruling in future cases. “I would not advise football coaches hoping to bully students into prayer to do that. It’s not clear the court supports you.”

In the dissent from the three members of the court’s liberal wing, Justice Sonia Sotomayor wrote that the court “misconstrues the facts.”

Sotomayor wrote that Kennedy had a “long-standing practice” of praying with students and that some students reported to the school district that they joined the prayer due to “social pressure.” The dissent also said Kennedy spoke to the reporters multiple times, causing disruptions that required the school to enlist extra security measures.

“It’s interesting that the court is not exhibiting any methodological consistency across these domains,” Case said of a number of the court’s recent decisions. “The court has yet to explain how only those rights it likes continue to be protected and the rest don’t.”

mabuckley@chicagotribune.com