For the past five years, Charles T. Sell, a St. Louis dentist, has been sitting in a federal prison hospital in Springfield, Mo., while doctors and lawyers try to figure out what to do with him.

The U.S. government indicted him on charges of Medicaid fraud in 1997, but courts have found him to be so mentally ill that he is not competent to stand trial. Those courts have agreed with government doctors who say the only hope of rendering him competent is to administer anti-psychotic drugs -- by force, if necessary -- but Sell, citing the drugs' sometimes debilitating side effects and his own constitutional rights, has refused.

Yesterday his case was the subject of an hour-long oral argument before the Supreme Court, by the end of which the nine justices seemed no closer to a satisfactory conclusion than the other courts that have wrestled with it.

In fact, the justices seemed to be having second thoughts about whether they should have agreed to hear the matter, asking attorneys for both Sell and the government whether the original federal district court order authorizing forcible medication should have been appealable at all. If it decides it lacks jurisdiction, the court could send the case back for a trial and deal with Sell's constitutional claims if he is convicted.

Both Sell's attorney and a representative of the Justice Department told the court that the case is ripe for review -- but that was the extent of their agreement.

The court has ruled in the past that the government may forcibly medicate a prison inmate -- already convicted of a crime -- who would otherwise be dangerous to others and who would be helped by the treatment. But it has also said the government cannot forcibly medicate a defendant during trial unless it shows that the person is dangerous and needs the drugs to improve.

In 2001, the justices declined to review a ruling by the U.S. Court of Appeals for the D.C. Circuit, upholding an order to medicate Russell Weston, a schizophrenic accused of killing two Capitol Police officers, so he would be competent for trial. And last month, the St. Louis-based U.S. Court of Appeals for the 8th Circuit, the same court that sided with the federal government in Sell's case, ruled that Arkansas prison officials could force a death row inmate to accept medication so he would be sane for execution.

Sell's case is novel because he has been charged with nonviolent offenses and the courts have not ruled him a danger to others. It is also somewhat unrealistically framed in the Supreme Court, because the federal government has also charged him with trying to intimidate a witness and hire a hit man to kill an FBI agent -- but neither of those charges is technically part of this appeal, and the justices must rule as if they did not exist.

Under the circumstances, forcing Sell to ingest mind-altering drugs would violate his rights to freedom of thought and to a fair trial, and would expose him to potential physical harm, Barry A. Short, Sell's attorney, told the court. "Dr. Sell has a right to make a choice," he said. "He is not a stupid person."

But the charges that Sell defrauded Medicare of hundreds of thousands of dollars, though nonviolent, are still so serious that the government's interest in resolving them outweighs those considerations, Deputy Solicitor General Michael R. Dreeben countered.

Summing up several justices' frustration with this conundrum, Justice Antonin Scalia asked Short: "What do you propose to do with this man? Let him go?"

Short responded that Sell would not necessarily be freed, but rather might be the subject of a government-initiated proceeding to commit him to a mental hospital.

Justices seemed baffled by that argument, which implied that Sell would rather extend his confinement -- in a hospital where the only proposed treatment so far is with anti-psychotic drugs -- than submit to medication for trial.

But Justice Anthony M. Kennedy seemed unimpressed with the government's rationale for trying to medicate someone who has only been charged with a crime, and is still presumed innocent.

"What is the authority of the government to forcibly medicate him at all . . . so he'll behave a certain way at trial?" he asked Dreeben.

"The government's authority is that Dr. Sell has been indicted on serious criminal charges," Dreeben responded.

Sell's mental illness has been diagnosed as "delusionary disorder, persecutory type" -- in an early phase of the case he behaved bizarrely, shouting racial epithets and spitting in the face of a magistrate judge. An irony is that his reported delusion revolves around the persistent belief that he is the victim of a government plot -- yet he is, in fact, sitting in federal prison, including extended periods in solitary confinement, facing an order that he be given anti-psychotic drugs.

As if to underscore this point, Justice John Paul Stevens noted that Sell has already been confined longer than he would have been if convicted on all counts of the Medicaid fraud indictment.

But Dreeben told the court that Sell has himself to blame for his extended stay behind bars, since he is one of only a handful of people who have ever litigated their refusal to be medicated to such an extent.

"Most individuals accept the fact . . . that medication is the appropriate, medically sanctioned way" to get better for trial, Dreeben said.

The case is Sell v. U.S., No. 02-5664. A decision is expected by July.

Justice Anthony M. Kennedy, left, with Justice Clarence Thomas, questioned the medication rationale.