The Bible has been a presence in American classrooms to at least some degree since before the origins of the country’s public school system in the 19th century.
But the announcement by Oklahoma’s state superintendent on Thursday that all public schools in the state must teach the Bible represented a major effort to expand its role and bring a Christian historical perspective to most all students. Schools have become the arena for an array of moral and cultural conflicts, and conservative Christians are asserting their political muscle even as they decline as a share of the American population.
“In Oklahoma, we are very proud to lead the country on pushing back on the leftists trying to rewrite history and say, No, we will teach from the Bible,” the superintendent, Ryan Walters, said in an interview on Friday.
Mr. Walters, a Christian conservative and former history teacher, said the mandate would focus on fifth through 12th grades, with an emphasis on the Bible’s influence in history and literature, areas where the Bible has historically been accepted in public education.
For example, he said, the Bible could be used in a lesson to understand the preamble to the Declaration of Independence, which says that all men are “endowed by their creator with certain unalienable rights,” or in a study of the Rev. Martin Luther King, Jr.’s “Letter From Birmingham Jail,” which includes references to Jesus and his teachings.
But he went further, saying that the Bible would also be woven across subjects including math and science, in which students could examine its influence on leading thinkers and ideas. Biblical instruction could also be offered in younger grades when applicable.
Mr. Walters, a Republican, said every teacher across Oklahoma would be expected to have a copy of the Bible in the classroom.
Mr. Walters made the announcement a week after Louisiana became the first state to order that public schools display the Ten Commandments in every classroom, prompting an immediate court challenge and denunciations from those who saw it as an encroachment on the separation of church and state.
In Oklahoma, the directive instructs schools to incorporate the Bible, “which includes the Ten Commandments,” into instruction.
Republicans and conservative Christians have increasingly sought to bring prayer and religious texts into public schools as they push against what they see as an encroaching liberal orthodoxy in public education, particularly on topics like race and gender identity. They seek a return to an era when Christians were a clear majority in America and the Bible was a far less contested presence in classrooms.
“Folks like Superintendent Walters aren’t wrong when they say the Bible historically was the most common schoolbook in the United States,” said Adam Laats, a historian of education at Binghamton University and a former middle and high-school teacher.
He said that in the 18th and 19th centuries, the Bible “was assumed to be the centerpiece of any education: reading, writing, arithmetic and basic Christian morality.” But as the country’s demographics evolved in the late 19th and 20th centuries, Professor Laats said, there was less consensus on the notion that moral instruction should be Christian in character.
That led to decades of legal wrangling and cultural clashes over the role of religion in public schools.
Those disputes culminated in a series of landmark Supreme Court cases, including a ruling in 1963 that mandatory Bible reading or prayer in public schools was unconstitutional. At the time, about half of school districts included some form of devotional Bible reading, according to Dr. Laats.
The ruling was interpreted by many conservative Christians as taking God out of schools, and it became a lasting symbol of what they have seen as a broader moral decline and societal chaos.
Today, several states, primarily in the South, offer Bible classes as electives in public schools, said Mark A. Chancey, a professor of religious studies at Southern Methodist University.
In Texas, electives include the study of the Old or New Testament and its impact and are limited to middle and high school students. About 1,200 students were enrolled in such courses this school year out of more than five million students statewide, according to state data.
Dr. Chancey, who has analyzed Bible curricula in Texas, said that instruction varied widely. Some courses are academically rigorous, with no promotion of a particular religious point of view. But more, he said, are “closer to Sunday school than public school.”
Oklahoma has a similar law allowing elective Bible courses for high school students, but legal experts say Mr. Walters’s mandate takes the state in a new direction, by requiring and infusing the Bible more broadly in coursework.
“This curricular mandate would teach religion to public-school children, whether or not their parents are willing or unwilling,” said Joseph Thai, a constitutional law professor at the University of Oklahoma.
He said the mandate could end up as a “test case” that could reach the Supreme Court.
The court, which gained a 6-3 conservative supermajority under former President Donald Trump, has increasingly embraced the role of religion in public life, including in schools.
In 2022, days after overturning the right to abortion under Roe v. Wade, the court issued a decision siding with a high school football coach who prayed at the 50-yard line after games. That opinion disavowed a major First Amendment precedent from 1971 and seemed to adopt a new approach: “In short, if there is no coercion by the government, then the government can accommodate and in some cases even promote religion,” Mr. Thai said.
Mr. Walters, who attends a Protestant church affiliated with the Church of Christ, said he would not favor a particular version of the Bible. And he said the book, unlike other religious texts, such as the Quran, played a unique role in American’s founding and culture.
“I don’t know how you teach history, I don’t know how you teach English, without the No. 1 best-selling book in American history as part of that curriculum,” he said.