The Supreme Court agreed Tuesday to decide whether school voucher programs like those favored by the Bush administration are a constitutional use of taxpayer money.

The court said it will hear three related cases arising from a program that provides tuition aid to parents of nearly 4,000 students in failing public schools in Cleveland.

Lower courts reached opposite conclusions about whether the program is unconstitutional government promotion of religion.

A high court ruling is expected by June.

The Ohio program offers the justices an opportunity for a broad ruling on a long-simmering political issue that generally pits social conservatives and some inner-city parents against civil liberties groups and teachers' unions.

School vouchers were a centerpiece of President Bush's education platform during his campaign, and his top Supreme Court lawyer filed an uninvited friend-of-the-court brief urging the justices to take on the Cleveland dispute.

Solicitor General Theodore Olson argued that the Cleveland program is constitutional, because it provides the same amount of cash help to students no matter whether they enroll in church-run schools or nonreligious private academies.

Vouchers, also called school choice programs, allow parents to take children out of public schools and use government subsidies to pay all or some of the tuition bill at a private or religious school.

Supporters say vouchers give children who want to learn a way out of hectic or dangerous public schools, while giving parents power over school bureaucracies. Opponents, including most congressional Democrats, say vouchers steal precious public money from the schools that need it most.

Although vouchers remain an ideological touchstone for many conservatives, there was not enough Republican support for vouchers when Congress recently passed a sweeping education reform package. Leaders shelved the idea temporarily.

Those who oppose vouchers on constitutional grounds say they are a clear violation of the guarantee that government will not promote or "establish" religion.

The court last ruled on vouchers directly in 1973, when it struck down a school voucher program because some public money was used to "subsidize and advance the religious mission of sectarian schools."

The court has become more conservative since then, and it has allowed pro-voucher decisions from lower courts to stand.

The current nine justices have declined previous invitations to rule on voucher or tuition programs in Wisconsin, Maine and Vermont, even as they allowed more government aid to religious schools for things like computers and remedial tutoring.

As in Ohio, lower courts across the country have divided over whether spending tax money on religious education is an unconstitutional violation of the separation between church and state.

The Ohio Pilot Project Scholarship Program provides tuition vouchers to kindergartners through eighth-graders enrolled in city schools. The money, up to $2,500 per child annually, can be used at private or parochial schools that sign up for the program and meet its requirements. Low-income families get preference.

Of the 3,700 students enrolled in the program, 96 percent attend religious schools.

The Ohio Supreme Court approved of the program, but the federal courts struck it down.

The cases are Zelman v. Simmons-Harris, 00-1751; Hanna Perkins School v. Simmons-Harris, 00-1777; and Taylor v. Simmons-Harris, 00-1779.