The historic decision should come Thursday in a case involving a pilot school voucher program in Cleveland that mainly supports students in religious schools. If the justices rule in favor of the Cleveland program, the decision would not only allow the voucher program to continue, but would give new life to President Bush's rather moribund proposal to make school vouchers part of national education policy.
High court majorities have been discovering gaps in the wall between church and state for three decades, at least when it comes to education.
But decisions in those three decades have concentrated on making sure religious groups were treated on an equal footing with secular groups, not on underwriting a religious education with public money. Which makes the impending probable decision in the school voucher case such a departure.
The outcome in the Cleveland case -- where school voucher money was used overwhelmingly to allow attendance at religious schools -- is considered so certain that voucher opponents have begun to put the best face on things.
The Century Foundation, generally a voucher opponent, told the media in an "issue brief" this week that "a decision in favor of vouchers could expose a central flaw in these efforts -- the success of pilot-level voucher programs cannot be replicated on a large scale." Other groups claiming credit for supporting or originating voucher programs are peppering news outlets with material that also seems to take the decision for granted.
What makes each side so sure of the outcome in the Cleveland case is simple arithmetic.
The Supreme Court's two key swing votes, moderately conservative Justices Sandra Day O'Connor and Anthony Kennedy, repeatedly expressed support for the voucher principle during argument in the case on Feb. 20.
Another court member who could join them might be liberal Justice Stephen Breyer, though his vote is considered less likely.
O'Connor, for one, has given false signals from the bench before, appearing to vigorously support one side only to vote with the other when push came to shove.
However, O'Connor's public stance in the case is consistent with how she has voted in past cases.
A look at the high court's case history on the separation of church and state over the last several decades reveals an evolutionary drift toward more public support for religious institutions.
Lemon vs. Kurtzman in 1971 produced the "Lemon test," either respected or reviled depending on which side of the fence you sit.
Under the three-pronged test, the Supreme Court ruled, a government action is constitutional if it has a secular purpose, it neither promotes nor inhibits religion and, finally, it avoids "excessive entanglement" with religion.
The Lemon test has evoked outright hostility from some current court members, such as Scalia, and skepticism from others, such as O'Connor.
In any event, the importance of the Lemon test has been diminished over the years.
In 1992's Lee vs. Weisman, a Supreme Court majority ruled that clergy cannot constitutionally lead prayer at high school graduations. In 2000's Santa Fe Independent School District vs. Doe, a court majority ruled that student-initiated, student-led prayer at football games is unconstitutional -- a ruling which brought a bitter dissent from the court's three conservatives.
One issue that has never been resolved by the high court is whether student-initiated, student-led prayer is constitutional at high school graduations. Two U.S. appeals courts have said that it is; one has said that it is not. In consequence, student-led prayer is constitutional at public school graduations in some parts of the country, and unconstitutional in others.
So far, the Supreme Court has refused to review such cases.
Two cases in 1993 indicated that a Supreme Court majority wanted to make sure that public institutions did not discriminate against religious groups.
In Lamb's Chapel vs. Center Moriches School District, the court said public school districts that let secular groups use their premises after classes for meetings cannot deny the same use to religious groups. In Zobrest vs. Catalina Hills School District, the court said the First Amendment's separation of church and state did not prevent a public school district from providing a sign interpreter for a deaf child at a religious school.
The principle was hammered home once again in 1995's Rosenberger vs. Rector, a case involving the University of Virginia. The court said publicly funded schools that support secular groups from student activity fees cannot deny that same support to religious groups on campus.
The first real erosion of the Lemon test came in 1997's Agostini vs. Felton. In Agostini, the court said that federally funded remedial teachers could help students in religious as well as secular schools. The ruling also recast the Lemon test "entanglement" prong as simply another factor to be considered, not an overriding one, when determining the constitutionality of a government action.
In contrast, 2000's Mitchell vs. Helms might be considered a prelude to the Cleveland voucher case.
In Mitchell, a four-justice plurality ruled that a federal program funding the public school loan of books, computers and other educational materials to religious schools is constitutional, as long as the government's purpose was "neutral" -- in other words, the effect of the program could in reality promote religion as long as the government's purpose was not to promote religion.
Interestingly, the plurality opinion by Thomas -- joined by Rehnquist, Kennedy and Scalia -- dismissed as irrelevant whether government aide was given directly to religious schools or passed through the hands of parents or students before going to religious schools. The indirectness of school vouchers -- the fact that money is given to parents, who then have the choice to spend it at a private secular school or a religious school -- is at the core of the argument by Ohio officials and the Bush administration that school voucher programs are constitutional.
O'Connor, joined by Breyer, wrote a separate opinion in Mitchell agreeing with the judgment but saying Thomas's prevailing opinion was too broad. O'Connor said public aid to religious schools is constitutional if it is not used for religious purposes.
But in all of those cases, the Supreme Court approved the use of schools funds for secular purposes in religious schools, or forced school districts and public institutions to place religious organizations on the same plane as secular organizations.
In none of those cases did the Supreme Court approve the use of public money to subsidize religious education across the board. If as expected, the court rules for school vouchers in the Cleveland case, it will have done just that.
A final coalition in the Cleveland voucher case could look much like the winning side in the Mitchell case, with O'Connor joining Kennedy and the three conservatives to form a five-vote majority -- result, 5-4 in favor of vouchers. With O'Connor writing separately to concur in the judgment but disagreeing with a four-justice plurality as to reasoning -- result, 4-1-4, in favor of vouchers. Or with O'Connor, joined by Breyer, writing separately but concurring in the judgment along with a four-justice plurality -- result, 4-2-3 in favor of vouchers.
In the case to be decided Thursday, everyone agrees that Cleveland schools were in severe crisis in the early 1990s, so much so that a federal judge placed the city's school district under the control of the state superintendent in 1995. In response, the Ohio Legislature enacted a school voucher pilot program.
As it turned out, only the Cleveland area was eligible under the program's provisions.
For low-income families who chose to send their children to public schools, the program provided up to $2,250 per child. If there was money left over, higher income families were granted $1,875 per child, as long as that amount covered 75 percent of the tuition.
In the 1999-2000 school year, 56 private schools participated in the program; 46, or 82 percent, were religious schools. Of the 3,700 students participating in the program that school year, 96 percent attended religious schools.
Some parents and public school students filed suit against the Ohio program, saying it violated the First Amendment's ban on the establishment of religion. A federal judge issued a preliminary injunction against the implementation of the program, but that order was eventually stayed by the Supreme Court.
The judge then ruled for the challengers. A federal appeals court upheld the judge, pointing out that the program mainly helped students attend religious schools, and that the restrictions on funding basically made religious schools the only type of private institutions that could afford to participate.
Ohio officials then asked the Supreme Court for review.
(Nos. 00-1751; 00-1777 and 00-1779, Zelman vs. Harris etc.)