The sweeping language of the decision in a Texas case, a crushing defeat for school-prayer advocates, could extend far beyond school sports events--eventually affecting graduation ceremonies, moments of silence, and more.
The court said a school district's policy of allowing such student-led prayers violated the constitutionally required separation of government and religion.
Champions of a strict church-state separation exulted.
"The court's decision signals a reaffirmation of the appropriate role of religion in public schools--one in which private religious expression is constitutionally protected but officially sanctioned religious observances are not," said David Harris of the American Jewish Committee.
Opponents were aggrieved.
"The government's 'benign neutrality' toward religion in this country is now nothing short of malevolent hostility," said Jan LaRue of the conservative Family Research Council.
Justice John Paul Stevens wrote for the court: "Nothing in the Constitution...prohibits any public school student from voluntarily praying at any time before, during or after the schoolday. But the religious liberty protected by the Constitution is abridged when the state affirmatively sponsors the particular religious practice of prayer."
As the latest word on a politically volatile issue that has bedeviled the nation's highest court for 40 years, the ruling offered a ringing endorsement of a landmark 1962 decision that outlawed organized, officially sponsored prayers in public schools.
"Worship is a responsibility and a choice committed to the private sphere," Stevens said.
When the Texas case was argued in March, an ABC News poll said two-thirds of Americans thought students should be permitted to lead such prayers.
And in Texas' Republican primary election that same month, 94% of voters approved a nonbinding resolution backing student-initiated prayer at school sporting events.
Texas Gov. George W. Bush, who had filed a brief urging the Supreme Court to uphold such student-led prayer, said Monday he was disappointed in the ruling.
"I support the constitutionally guaranteed right of all students to express their faith freely and participate in voluntary student-led prayer," said the Republican presidential candidate.
Democratic Vice President Al Gore, also running for president, had no immediate comment.
Gary Bauer, a former GOP presidential candidate, noted that Republican presidents appointed four of the court's six-justice majority. "This underscores that my party has got to be more serious about the men and women we put on the high bench," said Bauer, who now leads the Campaign for Working Families.
Stevens said the court recognizes "the important role that public worship plays in many communities, as well as the sincere desire to include public prayer as a part of various occasions so as to mark those occasions' significance."
But he added: "Such religious activity in public schools, as elsewhere, must comport with the First Amendment." That amendment prohibits an "establishment of religion."
Joining Stevens were Justices Sandra Day O'Connor, Anthony M. Kennedy, David H. Souter, Ruth Bader Ginsburg, and Stephen G. Breyer.
"Even more disturbing than its holding is the tone of the court's opinion," Rehnquist wrote for the three. "It bristles with hostility to all things religious in public life."
Stevens' opinion relied heavily on the court's last major ruling on school prayer, when in 1992 the justices barred clergy-led prayers--invocations and benedictions--at public school graduation ceremonies.
Monday's decision is sure to be cited in the inevitable challenges to student-led prayers at such ceremonies and could be powerful ammunition in attacks against laws or school policies calling for daily moments of silence for prayer or meditation.
In the Texas case, four high school students and their parents sued the Santa Fe Independent School District in Galveston County in 1995 over its policy of letting students elect a "chaplain" to lead "prayers" at graduation ceremonies and home football games.
Two families--one Catholic and one Mormon--challenged the policy. Their identities were sealed by the courts.
After their lawsuit was filed, the policy was changed to let student-elected representatives--no longer called chaplains--give a "message or invocation." Speakers were free to choose what they said so long as it promoted good sportsmanship.
The Supreme Court agreed only to focus on the football games, passing up the graduation-ceremony dispute.
Still to be decided before the 1999-2000 court term ends next week is a Louisiana dispute over the constitutionality of using taxpayer money to buy computers and other instructional materials for religious schools.
That ruling will affect federal efforts to connect every American classroom with the internet and could also carry significance for the politically charged legal fights over tuition vouchers--help for families who send their children to religious schools.