"I think it will be enormously harmful and very divisive," he said. "The reality of the matter is the only place these religious schools are going to be able to get the tuition money from is by raiding the public school treasury."
Decolibus said the Cleveland schools have already lost $43 million to the voucher program over the past three years.
But Dave Zanotti of the Ohio Round Table, which supports school vouchers, welcomed the decision and said vouchers are positive.
"After several years of this experiment with the Ohio School Choice plan, there's been no damage done to the Cleveland system," Zanotti said. "Voucher schools haven't stolen the best students or caused there to be financial difficulty."
Clint Bolick, vice president of Institute for Justice, the group that fought for the voucher program, called the court's ruling "the most important education decision since Brown v. Board of Education," the 1954 landmark Supreme Court ruling aimed at ending racial segregation in public schools. He said today's decision should give other programs much needed momentum.
"This was the Super Bowl for school choice and the kids won," Bolick said. "It means that states and the federal government can now look to all educational alternatives, including private schools, to secure educational opportunities for children who desperately need them."
The decision also sparked more debate in the controversy over separation of church and state, just a day after an appeals court ruled the Pledge of Allegiance unconstitutional because it mentions "under God."
Nathan Diament of the Union of Orthodox Jewish Congregations compared opponents of school vouchers to proponents of the decision Wednesday by the 9th Circuit Court of Appeals in San Francisco.
"The opponents of school choice partake of the same logic as those judges who ruled the Pledge of Allegiance was unconstitutional," Diament said. "They wish to banish religion from our public square."
But Barry Lynn, with Americans United for Separation of Church and State, said the Supreme Court ruling is "a major defeat for the principle of church-state separation."
"In the court of the United States today, apparently it's acceptable for all taxpayers to pay for the religious indoctrination of some children," Lynn said.
Lynn told reporters the battle is not over.
"Those of us who support public schools and support real religious freedom are planning to take this battle to Congress and to every state legislature," he said. "Our goal is to see that no further voucher programs are enacted anywhere in these United States."
Darren Toms of ABC affiliate WTAM Radio in Cleveland contributed to this report.