State prisoners seeking to challenge their cases in federal court now face a new obstacle as a result of a Supreme Court ruling yesterday that requires that they first make such appeals in state supreme court, even if that court is unlikely to take up the case.

The 6 to 3 decision in the case of an Illinois man convicted of raping an 87-year-old woman ensures that state panels will get the first crack at any constitutional problems in a case on appeal, but further restricts inmates' access to federal courts and could prolong the already lengthy appeals process.

"State prisoners must give the state courts one full opportunity to resolve any constitutional issues by invoking one complete round of the state's established appellate review process," Justice Sandra Day O'Connor wrote in the case, which split the justices largely on ideological lines.

Dissenting justices, led by liberal John Paul Stevens, said the decision "will impose unnecessary burdens on" prisoners and "delay the completion of litigation that is already more protracted than it should be."

The case concerns the writ of habeas corpus (Latin for "you have the body"), which is used to determine whether a person is lawfully imprisoned. The writ is an important avenue for inmates who claim that their convictions or sentences were constitutionally flawed. Over the past decade, the Rehnquist court has curtailed appeals of what has been known as the "Great Writ" in an effort to bring finality to drawn-out cases. In the same vein, Congress passed a law in 1996 that restricted prisoners' access to federal judges.

In the case before the court yesterday, O'Sullivan v. Boerckel, Darren Boerckel had been convicted of rape, burglary and aggravated battery in 1977, when he was 17. His convictions were upheld by a state appellate panel, and the Illinois Supreme Court refused to hear his petition. Renewing his appeals in the mid-1990s, Boerckel tried to challenge the constitutionality of his case in federal court, raising several grounds, including that he had not knowingly waived his Miranda right to remain silent, that a confession was coerced and that the evidence at trial did not support a conviction.

State prisoners generally cannot obtain federal review until they have exhausted their claims in state court. And a federal judge rejected Boerckel's petition because he had failed to include the three claims in his prior petition to the Illinois Supreme Court. But the 7th U.S. Court of Appeals reversed, saying that because the state court had no obligation to hear the appeal, Boerckel was not required to submit a petition there. According to filings in the case, the Illinois Supreme Court grants what is known as discretionary review in fewer than 5 percent of the criminal petitions it receives.

Yesterday, the U.S. Supreme Court reversed the appellate court's ruling, ruling that state prisoners must file petitions for discretionary review before going to federal court, even if state courts bypass most of the claims. O'Connor emphasized the "comity interests," the mutual respect, served by giving state courts the first opportunity to consider whether constitutional mistakes occurred. She was joined by Chief Justice William H. Rehnquist and Justices Antonin Scalia, Anthony M. Kennedy, David H. Souter and Clarence Thomas. Dissenting were Justices Stevens, Ruth Bader Ginsburg and Stephen G. Breyer.

David Mote, Boerckel's lawyer, said yesterday that it is unfair to force prisoners to engage in an exercise in futility and noted that many other state courts, like Illinois, take up only a small percentage of appeals. Because deadlines for a state appeal have passed, Boerckel now has no way to challenge his 1977 conviction.