A crack in the wall.

June 23 was a red-letter day for Mark Chopko.

Chopko, general counsel for the U.S. Catholic Conference, saw a major victory on parochial school aid at the Supreme Court. And analyzing the decision, he thought he saw something more sweeping.

"This portends well for a more realistic relationship between religion and government," he told Newsday. "What this case says is...that vouchers can be constitutional so long as they follow certain guidelines -- the have to be widely available, the can't create financial incentives to choose religious schools and they can't be skewed toward providing religious benefit."

Chopko's reaction wasn't surprising. The U.S. Catholic Conference, the lobbying and public policy arm of the Roman Catholic bishops, has long sought broad-based taxpayer funding for the church's parochial school system. The hierarchy's attorneys file lawsuits and legal briefs pushing for this goal and carefully comb each Supreme Court decision for every sign of retreat from church-state separation.

But many experts think the June 23 Agostini v. Felton ruling that Chopko applauded did not o quite as far as he hopes. The justices gave their blessing to an unprecedented form of taxpayer aid to religious schools, but they seem to have stopped well short of approving vouchers.

In Agostini the high court scrapped one of its own precedents, overruling the 1985 Aguilar v. Felton decision. In that 12-year-old decision, the justices held that public school districts could not use federal "Title One" money to send teachers into religious schools to offer remedial education classes. Doing so, the 5-4 court majority said, fostered excessive entanglement between church and state and created the appearance of a symbolic union between religion and government.

The high court's anti-separationists -- Chief Justice William Rehnquist and Justices Antonin Scalia and Clarence Thomas -- have long criticized Aguilar. Now, assisted by two moderate swing justices -- Sandra Day O'Connor and Anthony Kennedy -- the decision's fate was sealed. Bluntly declaring that "Aguilar is no longer good law," five justices joined forces to clear the way for publicly funded teachers to provide instruction in religious schools this fall.

Noting that the court's church-state policy has "significantly changed" since 1985, Justice O'Connor's majority opinion observed that the justices no longer hold "that all government aid that directly aids the educational function of religious schools is invalid."

She continued, "New York City's Title I program does not run afoul of any of the three primary criteria we currently use to evaluate whether government aid has the effect of advancing religion: it does not result in governmental indoctrination; define its recipients b reference to religion, or create excessive entanglement....[T]his carefully constrained program also cannot reasonably be viewed as an endorsement of religion."

(At the same time it overturned Aguilar, the high court also struck down portions of Grand Rapid v. Ball,a l985 companion case to Aguilar brought by Americans United. Grand Rapids dealt with a local program similar to Title One put in place by the school district of Grand Rapids, Mich.)

But the immediate effect of the Agostini ruling almost took a back seat in the media's coverage. Courtwatchers, analysts and friends and foes of church-state separation wanted to know what the Agostini decision might lead to. Specifically, had the high court opened the door to more direct forms of government aid to religious schools such as vouchers?

Pro-voucher organizations and religious groups insisted that Agostini would make their legal case easy; groups advocating church-state separation disagreed.

For example, TV preacher Jerry Falwell, founder of the now-defunct Moral Majority and a harsh critic of public education, was certain the high court's ruling will ultimately lead to religious school voucher subsidies.

"I am hoping," he observed in The Falwell Fax, a weekly newsletter distributed to supporters around the country, "that this great and long-overdue court victory is a stepping stone to achieving a voucher system that will enable Christian parents to choose a Christian education for their kids!"

Blasting the "so-called 'separation of church and state,'" Falwell urged supporters to call congress and demand enactment of a voucher program, noting that House Speaker Newt Gingrich (R-Ga.) is an enthusiastic proponent of religious school aid.

Michael McConnell, a University of Utah law professor and prominent proponent of the "accommodationist" school of church-state relations, which advocates closerties between religion and government, asserted that the Agostini decision "knocks the wind out of the sails of those who say vouchers are unconstitutional."

But other observers offered a dramatically different viewpoint. Barry W. Lynn, executive director of Americans united, conceded that the Agostini decision created"a major crack in the wall of separation between church and state."

"Thanks to this misguided decision," Lynn said, "taxpayers will be called on to pay for state-funded teachers inside religious schools."

But Lynn cautioned against reading more into Agostini than is necessary. The ruling is a disappointment," he observed, "but it would be wrong to read it as a blanket approval for government aid to religious schools. The court conceded that church-state safeguards are still essential. The question of vouchers and other forms of direct government aid to religious schools will have to wait for another day."

In an analysis prepared for Americans United, AU Legal Director Steven K. Green concluded that the Agostini decision "reaffirms some important safeguards that work against vouchers." O'Connor, he noted, made it clear that no federal Title One funds ever reach the coffers of religious schools. She also recited the regulations that prohibit publicly paid teachers from becoming involved in religious instruction while at parochial schools.

Thus Green and other separationists believe O'Connor's language indicates that she considers Title One a narrow form of aid, unrelated to the question of voucher plans that funnel tax dollars into the coffers of religious schools.

Other judges certainly see the decision that way. Just four days after Agostini was handed down, a state court judge in Vermont rejected vouchers and specifically ruled that Agostini does not authorize them.

Rutland County Superior Court Judge Alden T. Bryan held that the Chittenden School District may not pay for students to attend Mount Saint Joseph Academy, a Roman Catholic institution. In his ruling, Bryan insisted that vouchers are different from the indirect aid upheld in Agostini.

"In the present case...public funds would be used to pay employees of a religious institution, who are bound by their contract to incorporate the teachings of the Roman Catholic Church into their classes," wrote Bryan in his Chittenden Town School Dist. v. Vermont Dept. of Education decision. "This subsidization would not only create a' symbolic union' between church and state, it would create an actual and direct link. Publicly raised tax dollars would flow directly from the state to Mount Saint Joseph Academy."

But no one expects the clamor and speculation wrought by the Agostini decision to die down any time soon. The Vermont decision is on appeal and legal disputes are under way over vouchers in Ohio, Wisconsin and Maine. Several bills are under active consideration in Congress and the state legislatures.

And there's one thing Agostini shows clearly: The high court remains sharply divided over church and state. A three-justice bloc -- Rehnquist, Scalia and Thomas -- stand ready to demolish the wall of separation between church and state and would almost certainly uphold vouchers.

Justices Ruth Bader Ginsburg, David Souter, Stephen Breyer and John Paul Stevens hold to a more separationist course. Kennedy and O'Connor fall somewhere in the middle, giving them a powerful role as swing voters.

Souter, speaking for the separationists, sharply criticized the high court majority in Agostini for authorizing "direct state aid to religious institutions on an unparalleled scale, in violation of the [First Amendment's] central prohibition against religious subsidies by the government."

In a separate dissent, Ginsburg,joined by Souter, Stevens and Breyer, criticized the manner in which Agostini reached the Supreme Court. New York school officials and Catholic school patrons opposed to Aguilar asked that the 1985 decision be declared a dead letter, citing an obscure provision in the Federal Rules of Civil Procedure, and the court majority agreed.

Calling this back-door approach unprecedented," Ginsburg and her three colleagues argued that the justices should have waited until a new case raising the issue was filed in the lower courts and worked its way up.

For the short run, public schools are gearing up to implement the changes sparked by Agostini. The U.S. Department of Education in July issued guidelines to schools around the nation, reminding them of the church-state safeguards in the Title One program.