ASHINGTON, May 27 — The Supreme Court ruled today that police questioning in the absence of Miranda warnings, even questioning that is overbearing to the point of coercion, does not violate the constitutional protection against compelled self-incrimination, as long as no incriminating statements are introduced at the suspect's trial.

But a person subjected to such questioning can still bring a civil suit against the police for damages for violating the Constitution's guarantee of due process, the court ruled. These two conclusions were expressed in a fractured set of opinions that reflected an intense struggle among the justices to resolve the issues raised by a suit against a police officer in Oxnard, Calif., who persisted in questioning a gravely wounded suspect in his hospital bed despite the suspect's cries of pain and pleas to stop.

The suspect, Oliverio Martinez, was involved in a police shooting that left him blind and paralyzed. He is also suing the Oxnard police for excessive force in the 1997 incident.

As a result of the shifting coalitions on the court that produced tenuous majorities without a single majority rationale for any proposition, Mr. Martinez will be able to pursue a civil rights suit against the officer, Ben Chavez, on 14th Amendment due process grounds, although not on the basis of the Fifth Amendment's right against compelled self-incrimination. How much practical difference the distinction makes remains to be seen.

Justice Anthony M. Kennedy, who along with Justices John Paul Stevens and Ruth Bader Ginsburg said both bases for suit should be available, wrote in a separate opinion that Mr. Martinez might receive "much of the essential protection" from the due process suit he can now pursue as he could from the Fifth Amendment suit he initially sought.

The decision, Chavez v. Martinez, No. 01-1444, overturned a ruling by the United States Court of Appeals for the Ninth Circuit, in San Francisco, that had permitted the suit to proceed on both constitutional claims. As the appeal came to the Supreme Court last year, it appeared to present a rather straightforward issue, whether the Fifth Amendment protection against self-incrimination can be said to be violated when there has been no prosecution and no official use of any incriminating statements.

But the case turned out to be considerably more complex. Argued on Dec. 4, it was the oldest undecided case on the court's docket, for reasons that became apparent as Justice Clarence Thomas announced the result this morning. There were majority judgments but no majority opinion supporting them; instead, six justices wrote opinions that, when patched together, produced a result.

"So you can see I'm a consensus builder," Justice Thomas said with a wry smile when he finished providing an oral road map of what had become of the case to which Chief Justice William H. Rehnquist had assigned him.

Along with the chief justice and Justices Sandra Day O'Connor and Antonin Scalia, Justice Thomas found that "a violation of the constitutional right against self-incrimination occurs only if one has been compelled to be a witness against himself in a criminal case." He added that "the absence of a `criminal case' in which Martinez was compelled to be a `witness' against himself defeats his core Fifth Amendment claim."

Justices David H. Souter and Stephen G. Breyer largely agreed with this conclusion, voicing their concern in a separate opinion that a contrary conclusion could leave the police liable for civil damage suits for any failure to give Miranda warnings. There were therefore six votes to reject the self-incrimination aspect of the suit.

Justices Kennedy, Stevens and Ginsburg vigorously disagreed. "Our cases and our legal tradition establish that the self-incrimination clause is a substantive constraint on the conduct of the government, not merely an evidentiary rule governing the work of the courts," they said in a dissenting opinion by Justice Kennedy.

Justice Thomas, joined only by Chief Justice Rehnquist and Justice Scalia, also voted to reject the due process aspect. Saying, "There is no evidence that Chavez acted with a purpose to harm Martinez by intentionally interfering with his medical treatment," Justice Thomas said the questioning was justified by the urgency of the situation and did not violate due process. He noted that there was a "risk that key evidence would have been lost if Martinez had died without the authorities ever hearing his side of the story."

According to a tape of the questioning, Mr. Martinez said several times that he was dying and begged the officer to leave him alone.

Five justices voted to permit the due process suit to proceed. Justice Stevens said in a separate opinion that the questioning was close to torture and would have ruled for Mr. Martinez on that basis. But he agreed with the other four to let the Ninth Circuit consider the question in a remand.

This meant a 5-to-3 vote to keep the due process question open, and it left Justice O'Connor unaccounted for in this part of the case.

Ben Wizner, a lawyer with the ACLU Foundation of Southern California, which filed a brief on behalf of Mr. Martinez, said the decision, although in some respects a setback, would help "deter extreme police behavior." He noted that the court had accepted a case for its next term that directly posed the question, suggested by this case, of what the consequences should be of deliberate violations by the police of the requirements of the Miranda rule.

There were also these developments today at the court:

Secret Hearings

Without comment, it turned down an opportunity to decide whether the hundreds of closed-door deportation hearings in the months after the Sept. 11, 2001, attacks violated the First Amendment. The so-called special-interest hearings were closed to the public under a policy that also kept secret the names of the "special interest aliens," 500 of whom have been deported.

A group of New Jersey newspapers challenged the policy of blanket closings, arguing that the government should have to justify closing the hearings case by case. The newspapers won a nationwide injunction against the policy from Federal District Court in Newark. The Supreme Court granted a stay of that ruling in June, and the United States Court of Appeals for the Third Circuit, in Philadelphia, overturned that ruling in October. Subsequently, the United States Court of Appeals for the Sixth Circuit, in Cincinnati, disagreed with the Third Circuit analysis and ordered an open hearing for one deportee, Rabih Haddad.

Ordinarily, the conflict between the appeals courts would have given the Third Circuit appeal, filed by the American Civil Liberties Union, a good chance of getting the Supreme Court's attention. But in responding to the appeal, North Jersey Media Group v. Ashcroft, No. 02-1289, the Bush administration told the justices that the issue was of diminished importance because there was just a handful of "special interest" cases remaining and the government was engaged in an "ongoing review process" that could change the procedures and make the constitutional issues moot. The administration has meanwhile kept open the option of filing its own appeal from the Sixth Circuit ruling.

Airline Liability

The court agreed to decide whether death or injury on a commercial airline flight that results from the worsening of a passenger's pre-existing medical condition can lead to liability under the Warsaw Convention, the treaty that governs liability for airline "accidents."

The case, Olympic Airways v. Husain, No. 02-1348, is an appeal by the airline from a $1.4 million verdict won by the family of a doctor, Abid M. Hanson, who died of an asthma attack in 1998 on a flight from Athens to New York. He was seated in a nonsmoking section, as he had requested, but was only three rows from the smokers. A flight attendant refused his request to change seats.

Before the Ninth Circuit, the airline argued unsuccessfully that Dr. Hanson's death was not because of an accident, as that word is used in the treaty, because cigarette smoke in the cabin of a plane where smoking was permitted was not an unusual or unexpected occurrence. The appeals court found that the flight attendant's failure to respond was egregious under the circumstances and met the definition of an accident.