CHARLES LAVERNE SINGLETON is a death row inmate in Arkansas, convicted in 1979 of a brutal stabbing murder. He is severely mentally ill. The schizophrenia that now afflicts him was diagnosed after his conviction and death sentence. His psychosis can be controlled only with powerful drugs. Mr. Singleton sometimes takes his drugs voluntarily, but sometimes he must be forcibly medicated. So when Arkansas authorities set his execution date, they created an absurd dilemma for the courts. The Supreme Court has forbidden the execution of the mentally incompetent -- people who don't know what is happening to them or why. And there is little doubt that if Mr. Singleton stops taking his drugs, he will render himself incompetent. But the high court has also said that someone can be forcibly medicated only if he is a threat to himself or others and medication is in his best medical interest. So Mr. Singleton's case poses a morbid question: Can the state medicate an inmate, which is in his best medical interests, to make him competent for death, which is not?

That a federal court of appeals -- in this case the sharply divided 8th Circuit -- could approve such an idea suggests that the rules under which the legal system approaches such questions are not even coherent. If it is inhumane and cruel for the state to kill the insane, why is it any less so to dope the patient up first? Why, for that matter, if the state means to kill someone, does it matter if he understands what's going on in the first place? Might it not be more humane to let the condemned believe, as Mr. Singleton apparently does, that he will survive his execution?

The incoherence of American law's approach to mental illness is by no means confined to bizarre capital cases. Concerns about civil liberties have made it so difficult to medicate seriously ill people who need help that they end up committing crimes; then and only then does the system insist on treatment, so the mentally ill can be prosecuted and punished. And once a person faces charges, the system has little nuance. The insanity defense is difficult for jurors to accept in horrible crimes, for in many states, if accepted, it requires them to pronounce "not guilty" someone who clearly committed the crime. Prosecutors face enormous pressure to try such cases, rather than allow people who are obviously sick to be committed. The result is cases like Mr. Singleton's and that of Russell Eugene Weston Jr. -- whom the government is trying to medicate into competence to face trial for the 1998 shootings at the U.S. Capitol.

These absurdities are not necessary. People like Mr. Singleton ought to be medicated not to facilitate punishment but because failing to do so is inhumane. The legal system must develop the flexibility to deal with people who are both obviously guilty and obviously sick. The price of accepting treatment cannot be death.