Lawyers for Governor Bush yesterday asked the Florida Supreme Court to uphold the nation’s largest school voucher program, a centerpiece of his education reform policy, after an appellate court ruled that it violated the state’s constitution.

The closely watched case could affect thousands of schoolchildren in the Sunshine State and color debates elsewhere over school vouchers.

Since 1999, Florida has allowed parents in “failing” schools to use state vouchers worth $4,400 to help their children transfer to private schools.

As soon as the law was signed, it was challenged by Florida’s teachers unions and parents who opposed the program for siphoning money away from public schools. They were joined by groups such as the American Civil Liberties Union, the NAACP, People for the American Way, and the Anti-Defamation League, among many others, in suits now combined into Bush v. Holmes.

Last November, a Florida appellate court struck down the scheme, called the Opportunity Scholarship Program, because it allowed public-school dollars to flow to religious schools, contrary to a provision of the state constitution that bars “aid” to sectarian schools. The state obtained an injunction that has allowed the program to continue while the case is appealed.

Lawyers for the state and families that support the vouchers argued yesterday that the purpose of the program is not to aid religious schools, and that any benefit to them is incidental.

“The Opportunity Scholarship Program is in aid of Florida’s children, period. It is not a contrivance or a clandestine way to fund schools,” argued the Florida solicitor general, Christopher Kise.

More than half of the 741 children in the program used the vouchers to enroll in religiously affiliated private schools. An even larger number of disabled and special needs children use a similar program to receive special instruction.

Although the U.S. Supreme Court ruled in 2002 that a similar voucher system in Cleveland did not violate the federal prohibition against the establishment of religion, the Florida 1st Circuit court of appeals determined that the state’s constitution has much stricter requirements separating church and state in education than does the federal Constitution.

Article I, section 3 of the Florida Constitution states that “no revenue of the state…shall ever be taken from the public treasury directly or indirectly in aid…of any sectarian institution.”

“The Florida Constitution means something very specific. It means no funds, that first word is quite clear – no revenues shall be taken from the state, directly or indirectly, in aid of sectarian institutions,” a lawyer for the groups opposing the vouchers, John West, told the judges.

The program is also being challenged under a provision of the state constitution that obliges the government to provide a “uniform” and “quality” public education to all students.

A lawyer for the state, Barry Richard, said vouchers help fulfill that mandate by allowing children to escape failing schools even if those public schools would lose money.

“The Legislature and the government have made the determination that the child is more important than the institution,” he said.

The outcome of the Florida case will not bind other states. However, the court’s ruling could have a political impact and affect public perceptions of voucher proposals elsewhere, said advocates on both sides of the issue, many of whom watched the proceedings yesterday via a Webcast.

“If the scholarship program is upheld, that will clear the way for other state legislatures to move forward on school choice programs. If it ends, then other state legislatures will be hesitant to move forward,” said the director of the Center for Educational Freedom at the Cato Institute, a libertarian think tank, David Salisbury.

“There is no question: Since Florida is the leading state in the country on school choice, other states are watching what happens there,” said a lawyer for the Institute for Justice, Clark Neily, who argued yesterday on behalf of parents who use the vouchers.

If vouchers for children in kindergarten through 12th grade are struck down, other state programs that allow public funds to pay for services at private schools may also be vulnerable to attack, including specialized instruction for disabled students, pre-kindergarten programs, and even college scholarships that can be applied at religiously affiliated institutions, Mr. Neily said.

A win for vouchers would send the message that, “School choice is a civil rights issue of the 21st century. Nothing more sharply divides the haves and have-nots than people who have ability to choose where their kids go to school,” he said.

The legal director of People for the American Way, Eliot Mincberg, agreed that other Florida programs would be vulnerable, and the voucher movement nationwide would suffer if Mr. Bush loses.

“It would be an important blow against vouchers, both because Florida is the largest place to use them, and because it will reinforce the point that vouchers face a lot of legal hurdles even after the Supreme Court’s decision [in the Cleveland case],” he said.