A Florida appeals court delivered a blow to the heart of the school vouchers movement yesterday, declaring unconstitutional a statewide program that allows students in failing public schools to use taxpayers’ money to attend religious schools.

Governor Bush, who has made vouchers a key part of his education agenda, said the state would appeal the 1st District Court of Appeal’s decision, which would advance the case to the Florida Supreme Court, the state’s highest court.

Mr. Bush said he was “disappointed” by the ruling and warned that the state’s other vouchers programs would be threatened if the ruling were upheld.

“It’s unfortunate the plaintiffs continue to try to deny predominately poor and minority parents meaningful choices,” he said in a statement.

Opponents of vouchers said the court’s decision demonstrates that voucher programs have “serious constitutional problems,” said Joseph Conn, a spokesman for Americans United for Separation of Church and State, which is contesting the voucher program. Like many critics of vouchers, Mr. Conn said Florida and other states should be spending money on improving its school system rather than encouraging students to leave.

Supporters of voucher programs, which have also been started in Cleveland, Milwaukee, and Washington, D.C., say they offer the best hope for students stuck in failing schools and provide incentives for poorly performing schools to improve in order to keep attracting students.

While voucher programs in other states have suffered lower court defeats that were later overruled, the Florida appeals court decision underscores the difficulty supporters of vouchers will have in overcoming state constitutional law.

Florida is one of 37 states, including New York, with a “Blaine amendment” that bars public funding of religious institutions.

Florida’s constitution mandates that “No revenue of the state…shall ever be taken from the public treasury directly or indirectly in aid…of any sectarian institution.”

The plaintiffs in the case, which included civil liberties groups and the Florida Education Association, the state’s teachers union, first argued that the governor’s voucher program violated the federal Establishment Clause, which mandates the separation of church and state.

While the case was pending, the U.S. Supreme Court in 2002 issued a ruling declaring a tuition voucher program in Cleveland to be constitutional. The plaintiffs then focused their case on what they considered to be violations of the state constitution.

Without denying the merits of tuition vouchers, the court said it could not “ignore” the exact language of the state constitution, describing the state’s “Blaine amendment” to be more restrictive than the First Amendment.

The pro-voucher side in the Florida case argued that the governor’s voucher program does not directly or indirectly aid sectarian institutions because the vouchers are given to parents, who are free to decide where to enroll their children.

The court disagreed. “Such an indirect path for the aid does not remove the OSP from the restrictions of the no-aid provision,” wrote Judge William Van Nortwick in the decision.

“Courts do not have the authority to ignore the clear language of the Constitution, even for a popular program with a worthy purpose,” wrote Judge Van Nortwick. “If Floridians wish to remove or lessen the restrictions of the no-aid provision, they can do so by constitutional amendment.”

The pro-voucher side said if the no-aid provision excludes religious schools from the voucher program, the law would discriminate against parents who select those schools, violating the Free Exercise Clause of the First Amendment.

The court majority, citing the Supreme Court case Locke vs. Davey, said the Free Exercise clause does not require Florida to provide vouchers to students and that the state’s no-aid provision “is an expression of a substantial state interest.”

While supporters of vouchers in the case said the “Blaine” amendments were inspired by anti-Catholic bigotry in an attempt to prevent Catholics from establishing their own schools in the 1800s, Judge Van Nortwick wrote, “Whether the Blaine-era amendments are based on religious bigotry is a disputed and controversial issue among historians and legal scholars.”

Judge Van Nortwick said the state’s “no-aid” provision does not prohibit tuition vouchers from going toward nonsectarian schools.

Marcus Winters, a research associate for the conservative Manhattan Institute think tank in New York City, said restricting vouchers to non-religious schools “would significantly reduce the amount of choice students have.”

In the dissenting opinion, Judge Ricky Polston said the voucher program does not violate the state’s no-aid provision, declaring the program to be “neutral” and providing parents a “true private choice.”

He also called into question the majority’s understanding of the history of the Blaine amendments. “The majority is selectively picking and choosing from so-called history to avoid the appearance of giving effect to anti-Catholic bigoted language,” Judge Polston wrote.

Under Florida’s Opportunity Scholarship Program, which started in 1999, students receive vouchers if their school is identified as “failing” twice in a span of four years. A spokeswoman for Florida’s Department of Education, Frances Marine, said 732 students are using the vouchers this new academic year, receiving an average amount of $4,241 a student. Of those students, 385 attend religious schools.

Florida, which has more voucher students than any other state, has two other voucher programs, the McKay scholarship program for students with learning disabilities and a corporate income tax credit scholarship program for low-income students. About 25,000 students are using vouchers from those two programs.

Clark Neily, a senior attorney at the Washington, D.C.-based Institute for Justice, which represents families in Pensacola, Fla., whose children are using vouchers, said, “It’s a very open question in many states about how courts would rule in their own Blaine amendments.”

Mr. Neily noted that the New York State Court of Appeals in 1967 in the case Board of Education vs. Allen ruled that a law requiring school authorities to lend textbooks to private school students did not violate the state constitution or the Establishment Clause of the First Amendment. The court argued that the state law authorizing textbook loans benefits all school children, not just ones attending parochial schools.

Mr. Neily said a parallel could be drawn between the textbook case and school vouchers.

New York has shown little interest in adopting a voucher program, which is bitterly opposed by the teachers unions. Governor Pataki has been largely silent on the issue of vouchers, while Mayor Bloomberg has pinned his hopes for education reform on the creation of charter schools, which are publicly funded but privately run.