IN EDUCATION circles at least, the Supreme Court's decision upholding school vouchers resounded like a thunderclap.

A slim majority ruled that a Cleveland program did not violate the U.S. Constitution's separation of church and state. And before printers could cool down after churning out all 98 pages of the opinion, observers predicted the transformation of education as we know it, while critics darkly envisioned sectarian conflict.

But the results might not be that far-reaching or dangerous just yet. Although the court removed a cloud of constitutional uncertainty hovering over the few voucher programs in existence, experts do not believe that the decision will unleash a torrent of copycats around the nation that will, depending on whom you talk to, provide underprivileged inner-city children with the education they have long deserved, or imperil public schooling while inciting religious strife.

"I wouldn't expect much," said Jim Ryan, a professor at the University of Virginia's law school who teaches a class and has written articles about school vouchers. "Most suburbanites are opposed to school choice because they're happy with their schools, and they worry about any money leaving schools, and they worry about kids outside their districts - mostly urban kids - coming into their district."

Ryan said support for school vouchers is more limited than the two sides to the debate would make it seem.

"It really depends on Republican and African-American support in inner cities," he said. "Where that support exists, you will probably see limited voucher programs. But will that make much of a difference to the educational opportunities available to inner-city kids? Probably not much."

Since Ohio legislators established Cleveland's program in 1995, supporters and opponents knew their fight would take them to the Supreme Court.

The legislators passed the program because the Cleveland schools were so bad. Test scores were awful, morale was low, and only a third of high school students graduated. So the state took over the schools and offered parents up to $2,250 to send their children to participating private schools. More than 3,700 students signed up, and virtually all enrolled in Catholic parochial schools.

Basis for dispute

This energized the uproar and provided the basis for the legal dispute. Opponents said it violated the very foundation of American democracy: a First Amendment ban on state sponsorship of religion.

The critics noted a line of Supreme Court decisions dating to 1947 that zealously guarded this ban, and they looked to today's justices to step in and strike down the voucher program as a constitutional affront.

That the Supreme Court did not go along should not come as a shock. As Charles Fried, a Harvard law professor who helped defend Cleveland's program, said: "In light of the cases the court has been deciding the last dozen years, this is the way it should have gone."

The court's thin conservative majority, led by Chief Justice William H. Rehnquist, have gradually been approving various kinds of state aid to religious schools, starting with tax deductions for parents' expenses and moving on to, most recently, the public funding of schools' purchase of equipment.

The swing vote

For Justice Sandra Day O'Connor, the swing vote, the key to the Cleveland program's constitutionality was that it was merely part of an array of city efforts to improve education. Far more children and far more money, O'Connor emphasized, went to magnet schools and charter schools than to the parochial schools in the program. That added up to "true private choice," O'Connor said. This meant Cleveland parents were not coerced into sending their children to a Catholic school, but wanted to of their own accord.

"The scale of the aid to religious schools approved today is unprecedented," retorted Justice David H. Souter, who took the unusual step of reading his dissent from the bench to emphasize his disagreement. With nearly 97 percent of voucher students attending parochial schools, "something is influencing choices in a way that aims money in the religious direction," he said.

Two other dissents

In separate dissents, Justices John Paul Stevens and Stephen G. Breyer joined Souter in worrying that this would lead to religious disputes akin to the conflicts in Northern Ireland and the Middle East.

But it will take a lot more than the Supreme Court's decision to reach that point. Experts said the immediate impact of the decision is to shift the volatile debate over school vouchers away from the federal courts. Some opponents sought to dilute the victory by stressing that some state constitutions have stricter limits on state sponsorship of religion than the federal constitution and vouchers would now have to pass those tests. In any event, it remains up to state legislatures to enact voucher programs.

And there is no guarantee of that. In Maryland, the General Assembly has reacted coldly to reform proposals, said Patricia Foerster, president of the Maryland State Teachers Association, a voucher opponent. Legislators have rejected measures that would have established charter schools, Foerster said, and vouchers have never even come up.

MSTA would oppose

The 56,000-member association would fight any voucher proposal, Foerster pledged. Superintendent Nancy S. Grasmick doubted that vouchers would take root in Maryland.

Of course, that does not mean that there won't be any fights. "Now that the legal question has been settled," said Ronald J. Valenti, superintendent of the 98 Catholic schools in the Archdiocese of Baltimore, "we can put the energy and effort into getting that passed through the legislature." Nodding to a lack of public support for vouchers present in some but not all opinion polls, Valenti said the effort would first require convincing the public about the virtues of such a program.

So in the wake of the Supreme Court's voucher decision, opponents could take comfort in knowing that the battle over vouchers was not up, and supporters expressed resolve as much as jubilance with their constitutional triumph.

"There have always been two major barriers - legal and political - and this removes one," acknowledged Jeanne Allen, president of the Center for Education Reform, a Washington group that supported Cleveland's program. "This means there is less of a fight, but there still is one."