Should religion be in public schools? For a long time, the answer from the U.S. Supreme Court was no.

But in recent years, the court has blurred the sharp line between church and state in schools. Now, a Louisiana law has the potential to overturn decades of precedent.

The policy requires public schools to display the Ten Commandments in every classroom in “large, easily readable font.” It’s drawn national controversy.

“I did not know that the Ten Commandments was such a bad way for someone to live their life,” said Gov. Jeff Landry “I believe that the legislature was only following the will of the people in the state.”

In 1980, the Supreme Court ruled on the issue, saying states can’t put the religious document in schools.

After Louisiana’s law passed, Landry reportedly told a room of Republican donors he would sign it, adding “I can’t wait to be sued.”

A lawsuit from nine Louisiana families came quickly. The plaintiffs, who are Jewish, Christian, Unitarian Universalist and non-religious, include parents who are pastors and reverends.

The state’s attorney general, Liz Murrill has asked a federal court to dismiss the case, arguing it was filed “prematurely,” since the law doesn’t take effect until January. The first hearing in the case will take place in Baton Rouge on Monday.

Over the summer, Landry and Murrill held a press conference to make their case.

The two stood at a podium flanked by large posters displaying the commandments along with references to the doctrine, including Martin Luther King Jr.’s rules for protestors and a song from the musical Hamilton. They argued the document isn’t strictly religious and has historic value.

“It shows how ubiquitous, how frequent the Ten Commandments comes up in our culture,” Murrill said.

For parents who don’t want the rules in their kid’s classroom, Landry said, “Just tell the child not to look at it.”

Landry has supported a number of laws that expand religion in public education, including one that allows public schools to hire chaplains. At the press conference, he said he was surprised by the blowback over the Ten Commandments.

“Really and truly, I don’t see what the whole big fuss is about,” he said.

Critics argue Louisiana’s law violates the First Amendment, which protects freedom of religion. In fact, the U.S. Supreme Court struck down a nearly identical law more than 40 years ago.

The court said in Stone v. Graham that requiring schools in Kentucky to post the Ten Commandments “had no secular legislative purpose,” was “plainly religious in nature,” and unconstitutional. 

The ACLU is challenging the law along with Americans United for Separation of Church and State and the Freedom from Religious Foundation. The firm Simpson Thacher & Bartlett LLP is providing pro bono counsel. (Murrill said the state will handle its defense in house and doesn’t have a separate budget for the case.)

“The premise of the Constitution is that religion is something that is private and it succeeds best when the government just stays out of that conversation,” says Andrew Perry, a lawyer on the case with the ACLU of Louisiana.

Katherine Stewart, the author of “Money, Lies, and God: Inside the Movement to Destroy American Democracy,” has written several books on the rise of Christian nationalism in the United States. She says for supporters of Louisiana’s law, the goal is to change legal precedent.

“They think they can get the Supreme Court to overturn that ruling,” she says.

Stewart says it’s part of a movement to embed conservative Christian beliefs in government and other public institutions.

Louisiana’s legal argument relies on what’s known as a “history and tradition test,” Stewart says. The standard allows judges to argue the present can be disregarded in favor of the past.

The state’s law requires the Ten Commandments be displayed along with a statement saying the rules were “a prominent part of American public education for almost three centuries.”

The Supreme Court has a conservative supermajority. If the justices throw out Stone v. Graham like they did with Roe v. Wade, that would open the door for dramatic change. In this case, for the role of religion in public schools to grow.

“The reason Christian nationalist leaders and activists are fighting for this is because they know symbolism matters,” Stewart says. “It matters because it suggests there is one group in society that is above all the rest.”

Robert Hogan studies state politics at LSU. He says elected officials in Louisiana are responding to people who want more religion in schools.

“They will tell you, ‘What’s wrong with schools? Well, they took prayer out of schools, right?’”

The state has a lot of conservative Christians. Hogan says while this law may not have been at the top of most voters’ priorities, the fact it easily passed the legislature — with votes from even some Democrats — shows it has public support.

So while Landry is playing to his base, Hogan says it’s also an opportunity for him to get attention nationally.

“Even if he loses on this, maybe even especially if he loses on this, he sends a signal that he’s willing to fight for these things and is willing to push the envelope in whatever way he can to achieve the aims of Christian conservatives,” he says.

Stewart says the goal of the Christian nationalist movement is to erode support for public schools so that more money can be directed to private institutions.

She says by dividing people over things like the Ten Commandments “reduces faith in public education overall among all groups. And that softens the ground for a wholesale assault.”

The Supreme Court has already opened a path to religious charter schools. Some states are sending more money to private schools through expanded vouchers.

Louisiana recently passed a universal program that, if fully funded, would give any family that sends their kid to private school, secular or religious, tuition money.

Landry insists the state’s new law has less to do with religion and more with morals. “Repeat this: That the people of Louisiana in a bipartisan measure spoke through this bill.”

The state’s law takes effect on Jan. 1, though the court has blocked the policy from being implemented until at least mid-November as the lawsuit makes its way through the courts.