WASHINGTON − A divided Supreme Court on Thursday blocked the creation of the nation's first religious charter school, a major loss for those advocating a greater role for religion in public life.

The court split 4-4 over whether to allow St. Isidore of Seville Virtual Charter School, leaving in place the Oklahoma Supreme Court's decision that a religious charter school would violate the Constitution’s clause aimed at keeping religion separate from government.

Justice Amy Coney Barrett did not participate in the decision, leaving the nine-member court evenly divided. Although she didn't give a reason, Barrett is close friends with the Notre Dame Law School professor who was an early legal adviser to the Catholic Church in Oklahoma, which wanted to open St. Isidore.

The court issued its one sentence decision announcing the deadlock three weeks after hearing oral arguments. The announcement did not include how each of the participating justices voted.

Because neither side had a majority, no precedent was established by its decision.

But Neal McCluskey, director of the Cato Institute’s Center for Educational Freedom, said the stalemate could still send the message that “the right way to address discrimination against religion by our public education system is through private school choice programs, not charters.”

Annie Laurie Gaylor, co-president of the Freedom From Religion Foundation, called the decision a “crucial, if narrow, win for constitutional principles.”

“A publicly funded religious charter school would have obliterated the wall of separation between state and church,” Gaylor said in a statement. “We’re relieved that, at least for now, the First Amendment still means what it says.”

Case put First Amendment's religious clauses in tension

During oral arguments, the court's conservative majority seemed sympathetic to the Catholic Church’s proposal, which would have been a major expansion of the use of taxpayer money for religious education.

But one of the five conservative justices who participated in the case eventually sided with the three liberal justices concerned about the erosion of the separation of church and state.

Chief Justice John Roberts appeared to be the key vote, indicating that he saw religious charter schools as a more complex situation than those in which the court has steadily expanded the use of public funds for faith-based schools.

The case put in conflict the First Amendment's prohibition of the establishment of religion against its protections for the free exercise of religion.

In some recent cases where those portions of the Constitution have been in tension, the Supreme Court came down on the side of protecting religious exercise, expanding the role of religion in public life.

Under the same reasoning, the Archdiocese of Oklahoma City and the Diocese of Tulsa said they should be able to operate a K-12 charter school even though the curriculum would include religious instruction.

Oklahoma's governing body for charter schools voted 3-2 to approve the church’s application. Oklahoma Attorney General Gentner Drummond sued the governing body, arguing the charter school board’s contract with the church’s nonprofit corporation was illegal. 

Oklahoma attorney general warned of `chaos and confusion'

The Oklahoma Supreme Court ruled 6-2 last year that charter schools – which use taxpayer money but have private operators − are public schools and state law requires public education to be secular.

“Oklahoma’s charter schools bear all of the hallmarks of a public school identified by this Court and more,” Drummond, a Republican, told the U.S. Supreme Court, when he urged them not to get involved.

That’s why 46 states, including Oklahoma, and the federal government define charter schools as public schools, he said.

 If Oklahoma’s requirement that charter schools be both public and nonsectarian is unconstitutional, his office argued, then so are everyone else’s – a result that would create “chaos and confusion for millions of charter-school students.”

Catholic Church said charter schools aren't `public'

Both the state’s charter school board and the nonprofit created by the Catholic dioceses asked the U.S. Supreme Court to weigh in. 

They argued that charter schools aren’t “public,” because that terms applies only to the fact that charter schools are free to students and funded through taxpayer dollars.

Charter schools retain enough independence from the state to keep it from being a government entity, they say. And once the state allowed private entities to operate charter schools, blocking the Catholic Church from doing so would unconstitutionally discriminate against religion.   

Because no student has to attend the school, the government is not imposing religion on anyone, they argued.

Trump administration backed religious charter school

Under the Trump administration, the Justice Department changed its position that charter schools act like government entities. The court granted Trump’s solicitor general time during the oral arguments to make its case that Oklahoma can’t bar religious charter schools.

Oklahoma’s governor and attorney general – both Republicans – were on opposite sides of the issue.

Drummond, said allowing the Catholic charter school would “open the floodgates and force taxpayers to fund all manner of religious indoctrination, including radical Islam or even the Church of Satan.”

Oklahoma Gov. Kevin Stitt criticized what he called Drummond’s “open hostility against religion.”

Charter school alliance called case an `existential threat'

The National Alliance for Public Charter Schools had warned a win for St. Isidore would be an “existential threat not just to the fabric of public charter schools, but to their continued existence.” If charter schools were considered private, not public, that would jeopardize the funding of charter schools in states that ban public funding for private schools, they told the Supreme Court.

Some states might have been unable or unwilling to sponsor private charter schools, which would stifle public school innovation, the association said.

"With this legal clarity, we can move forward with renewed focus on expanding access to high-quality public charter schools for every family nationwide," Starlee Coleman, the group's president, said in a statement after the decision.

More religion clause decisions are coming

The case was just one of three cases about the First Amendment's religion clauses the court agreed to hear this year.

A decision is pending on whether Maryland parents who object to storybooks with LGBTQ+ characters should be able to get their children excused from elementary school classrooms when the controversial reading materials are being used.

And the court is also deciding a dispute over an employment tax exemption for a Wisconsin Catholic charitable organization – a case that could affect how easily tax exemptions are granted for any operation with a religious affiliation.