RELIGION was not really the issue in the Tennessee schoolbook case, but rather religious tolerance. The schools of Hawkins County, like many throughout the country, use a certain series of textbooks to teach reading, and a group of parents objected. Passages in the books offend their religious beliefs, they argued, and expose their children to ideas repugnant to their own convictions -- not only the theory of evolution but a great range of writing that seems to them to have religious significance. That, they said, violates their rights under the First Amendment. Last fall a federal judge agreed, ordering the county schools to excuse those children from reading classes.

Fortunately, the Sixth Circuit Court of Appeals has now reversed that decision. The case is one of several involving school curriculum and fundamentalist Christians' objections to it that are apparently on their way to the Supreme Court. But the appeals court has performed the service of stating the question correctly and returning it to the American constitutional tradition from the byways into which it had drifted.

Most parents will feel a degree of sympathy with the plaintiffs in Hawkins County. Bringing up children requires a family to fight for its own values against the outside world, and it's not only fundamentalist Christians who sometimes find themselves compelled to carry on that struggle with passionate energy. There are clearly limits to the things to which the government, through the schools, can subject a child.

But, the appeals court held, Hawkins County didn't overstep those limits. It could not have constitutionally required children to take part in a ritual -- the salute to the flag, for example -- that offended their religious beliefs. Nor could it have forced them to affirm views different from their own. But, the court said, it can require them to listen to differing views and discuss them.

Some of the assigned reading, the Hawkins County parents objected, seemed to suggest that all religions were equally valid. One mother testified that she did not want her child encouraged to make critical judgments on those subjects for which the Bible provides the answer. Chief Judge Pierce Lively replied with the useful distinction between religious and civil toleration. No child can be pressed to accept another's religion as true. But in a public school, all religions do indeed have equal standing.

Judge Cornelia G. Kennedy went one useful step further. Introducing students to "complex and controversial social and moral issues" is, she held, essential preparation for citizenship. Parents cannot be allowed to pull their children out of these discussions, she wrote, because the public schools have a compelling interest in -- a line from a Supreme Court decision a generation ago -- "promoting cohesion among a heterogeneous democratic people."