The U.S. Supreme Court has let stand a ruling that the New York City school system must pay private school tuition for disabled children, even if the parents refuse to try public school programs first. But the justices are likely to take up the issue again soon, with nationwide implications. The case has been closely watched by educators. Almost seven million students nationwide receive special-education services, with 71,000 educated in private schools at public expense, according to the federal Education Department. Usually, districts agree to pay for those services after conceding that they cannot provide suitable ones.