Boston ? May I interrupt the conversation about weapons of mass destruction for just a moment to talk about weapons of individual destruction? Can we turn our thoughts briefly from the fate of innocent civilians to the fate of convicted criminals? To the times when the logic of law leads, one step at a time, to the lunacy of law?

Such is the case of Charles Laverne Singleton, madman and resident of Arkansas’ death row. Earlier this month, the 8th Circuit Court ruled that Singleton could be forcibly medicated in order to make him sane enough to be executed. In a courtroom drama that turned into theatre of the absurd, the judges said he must be cured to be killed.

Here are two undisputed facts about Singleton: (1) He is a murderer, and (2) he is psychotic. Singleton stabbed a grocery clerk to death in 1979, three years after the Supreme Court reinstituted the death penalty. He descended into raving, delusional mental illness in 1987, one year after the same Supreme Court ruled that states couldn’t execute a crazy person.

In the case of Ford vs. Wainwright, the justices declared it was “cruel and unusual punishment” to execute someone who was mentally incompetent — so incompetent that he didn’t understand his fate or the meaning of death or why he was condemned. The decision was welcome but the standard was so low that even Rickey Ray Rector passed the so-called Ford test in 1992 — when Bill Clinton famously came off the campaign trail to authorize his death. Rector, it should be remembered, went off to his execution, leaving some of his last meal, a piece of pecan pie, to have “later.”

Today, the insanity defense is notoriously unsuccessful. But the courts have heard a rash of cases about mental competency, mental illness, medication and legal rights. At this moment, Russell Eugene Weston Jr., is being forcibly medicated so that he can stand trial in the 1998 fatal shooting of two guards in the U.S. Capitol. Meanwhile the Supreme Court has decided to hear the appeal of dentist Charles Sell, asking whether it’s legal to forcibly medicate a mentally ill man so he can face a civil trial, in this case for Medicaid fraud.

This is an age when mental illness often seems like a matter of chemistry. In the judicial system, there are many reasons to force medication on a delusional defendant: How can an irrational man make rational decisions about his treatment, let alone his trial? There are reasons to worry about it as well: What happens when a defendant comes to court “cured” and the jury sees a “different person” than the one who committed a crime?

But the ethics of treating a patient and defendant for mental illness get far more compelling when the death penalty is involved.

When Singleton first was diagnosed as psychotic — possessed by demons — he was under a stay of execution. It could be said that he was medicated for his own good. Sometimes he took the medication voluntarily, sometimes forcibly; sometimes it helped, sometimes it didn’t. But when the stay was lifted and he was back on track for execution, defining “his own good” became a much dicier proposition.

In the Circuit Court opinion, one of the judges wrote that “eligibility for execution is the only unwanted consequence of the medication,” as if execution were a mere side effect of the drugs like, say, dry mouth. But if it’s unethical, by AMA standards, for doctors to participate in executions, how can it be ethical to treat someone if the cure is, literally, more deadly than the disease?

Singleton’s case, which will be appealed to the Supreme Court, is part of the chaos and uncertainty and unease swirling around the death penalty.

In the past year, it became unconstitutional to execute the mentally retarded. But we can still execute juveniles. Since arriving in office, Atty. Gen. John Ashcroft has ruled 28 times that local district attorneys must pursue the death penalty, against their own judgment, in the name of “consistency.” But leaving office, Illinois Gov. George Ryan commuted death sentences for 164 men and three women, saying, “Our capital system is haunted by the demon of error — error in determining guilt and error in determining who among the guilty deserves to die.”

Much of the controversy over the death penalty is, as it should be, about guilt and innocence and error. But the way we deal with the mentally ill, the incompetent, strikes at the moral heart of the matter.

Singleton faced a bizarre choice between a lifetime sentence of insanity or the cure of a death sentence. As for those who believe that the death penalty can be reasonable and fair? The story of Charles Laverne Singleton has ended that delusion.

Ellen Goodman is a columnist for Washington Post Writers Group.