The true measure of the U.S. Supreme Court's favorable ruling on the Cleveland schools voucher program will be the ultimate fate of public school systems where school choice is an option. If, instead of complaining about sharing state money with alternative education systems, public schools and teachers raise the academic bar to aggressively compete for students, the high court's voucher decision may not be the death knell to public education critics claim.

On the other hand, if the court's ruling - that Cleveland's voucher program does not violate the constitutional wall separating church and state - drains public school systems of their most motivated students and parents as well as vital operating funds, the schools left behind could have little and less to work with.

We have not rejected the school voucher experiment out of hand on the premise that it might force failing public schools to make the grade or lose out to educational competition. The public school system in Cleveland is one of the worst in the country. Parents understandably jumped at the chance to yank their kids out of chaotic, dangerous, and academically challenged schools and enroll them in schools known for quality education.

Moreover, in a 5-4 decision, the court said parents were well within their constitutional right to do so with public money providing their school choices theoretically included public, private, and parochial options.

Theoretical choices were key to the court's reasoning with the Cleveland case, where more than 95 percent of students participating in the voucher program attend Catholic or other religious schools.

In principle, at least, students could attend secular, suburban, or charter schools with their $2,250 check from the state if those schools had signed up to accept voucher students. The fact that only a handful have in the Cleveland area is not the fault of the program itself, say its backers.

In writing for the majority, Chief Justice William Rehnquist said there was no dispute that the voucher program being challenged was "enacted for the valid secular purpose of providing education assistance to poor children in a demonstrably failing public school system."

He argued that the only preference in the program was a preference for low-income families to receive greater assistance and priority admissions at participating schools.

Dissenters, of course, could not get past the constitutional line between church and state that they believe was crossed in the Cleveland case. "On one side of every one of them [line] is an otherwise sympathetic case that provokes impatience with the Constitution and with the line," wrote Justice David Souter. "But constitutional lines are the price of constitutional government."

Wherever the voucher experiment leads us in this country, the message for foundering public school districts is simple: no more business as usual. America's children shouldn't have to settle for less in their public school classrooms. The great challenge for America's educators is to replace a losing formula that doesn't teach with one that finally emphasizes competitive success.