When the Supreme Court called a halt to school prayer 20 years ago, one critic suggested that the court's crier add to his usual words ("God save the United States of America and this honorable court") the following: "And in your wisdom show it the error of its ways." The advice went unheeded. But Ronald Reagan's espousal of a school prayer amendment in the White House Rose Garden yesterday may show that even unuttered prayers are answered.

Others suspect a tincture of politics. The restoration of "voluntary prayer" in public schools has been a top item on the Reagan administration's agenda of social issues. Polls suggest that a majority of Americans would approve. They presumably agree with Justice Potter Stewart's complaint in the original prayer case that a non-sectarian "voluntary" prayer is not "an establishment of religion" but only a recognition of the "deeply entrenched and highly cherished spiritual tradition of our nation."

That view appealed to me at the time and still does--up to a point. It was and is highly disputable that the First Amendment erects "an eternal wall of separation between church and state," or commands a coldly "neutral" attitude on government's part toward religion.

Unfortunately, a constitutional amendment creating a new "right" to pray "voluntarily" in public schools would be more than a return to the pre- 1962 status quo. What is positively affirmed as a constitutional right is not the same as what was tolerated as a matter of relatively harmless custom. Before the court's "Regents Prayer" decision, school prayer and Bible reading (also later foribdden) were scattered customs, mostly observed in the heavily Protestant South and Midwest. Elsewhere, they had always been a source of friction and contention, complicating ethnic and religious rivalries.

Those who are serious enough about school prayer to push for a reversal of Supreme Court rulings are presumably serious enough to insist that their prayers and practices bear the official stamp. So an affirmative "right" of school prayer is likely to become a recipe for renewed friction. It is equally likely that judges who must interpret the new "right" would be forced to decide which prayers pass constitutional muster and which do not: a form of "entanglement" of church and state from which sensible judges will shrink.

In retrospect, the 1962 ruling seems a less startling departure from custom and constitutional doctrine than some of us thought at the time. The Regents Prayer decision recognized an important truth: that religion is an intensely personal and private matter, deserving protection from the tendency of officials to dilute it into a bland civic ritual.

That was the point Justice Robert Jackson made in his notable dissents in previous church and state cases. In one, he made this waspish, and to my mind conclusive, comment: "My evangelistic brethren confuse an objection to (religious) compulsion with an objection to religion. It is possible to hold a faith with enough confidence to believe that what should be rendered to God does not need to be decided and collected by Caesar." Jackson's words need a closer look by Reagan and the "evangelistic brethren" who gathered with him in the Rose Garden yesterday. They not only seek a right to pray where my prayer and yours may not be the same. They also are mobilizing Caesar for duties better left in other hands.