WASHINGTON — In one of the most important cases of the term, the U.S. Supreme Court last week considered whether it is cruel and unusual punishment for the state to execute a mentally retarded person, even if that person committed a terrible crime.

By most accounts, the answer, expected in the next few months, will be yes, we must spare the lives of condemned criminals who are mentally retarded because ”evolving standards of decency“ demand it.

When the court last considered this question 13 years ago, just two states banned execution of the mentally retarded — not enough to warrant making the ban nationwide, the court concluded. Now, of the 38 states with the death penalty, 18 exempt the mentally retarded. Add to those the 12 states without a death penalty, and the total jumps to 30 out of 50, a ”supermajority,“ as Justice Ruth Bader Ginsberg put it.

Justice Sandra Day O‘Connor, considered the swing vote in what will likely be a 5-4 decision, made it clear she is looking for a ”national consensus“ on the issue. Her comments throughout the hourlong arguments indicated a strong leaning in that direction. At one point she asked, ”Should we not look to legislative enactments as the surest indication of the views of the states?“

Those hoping for a favorable court ruling go well beyond the legion of death-penalty opponents. Many death-penalty supporters — especially in execution-heavy states like Texas and Virginia — worry that putting mentally retarded people to death erodes popular support for state-sanctioned killing. Banning such executions lends an aura of compassion to the death-penalty machine, affording backers more leeway to expand the parameters for capital killings among other, less sympathetic offenders, such as terrorists and serial killers.

A federal ban on killing condemned murderers who are mentally retarded could halt the executions of hundreds of death-row inmates nationwide, with as many as 60 in California alone. But it would also raise a potentially far more difficult question: Who exactly should be spared? It will likely be left to the states to decide who among some 3,700 death-row inmates nationwide deserves such a reprieve. This task promises to be most cumbersome in California, home to the nation’s largest death row.

California does not have a law sparing the mentally retarded, largely because of a Democratic leadership fearful of being pegged soft on crime. No one knows how many of the nearly 600 men housed at San Quentin (plus 12 women at Chowchilla) could seek to have their death sentences changed to life without parole because of mental retardation. Estimates of mental retardation in the general population run between 1 percent and 2 percent, and between 4 percent and 10 percent among the prison population. Of the 10 inmates executed since California re-introduced the practice a decade ago, none has raised the issue of serious mental retardation.

Most of the states that ban execution of the mentally retarded use this definition: IQ at or below 70, inability to perform some basic daily functions and presence of the disability before age 18. Despite these parameters, the decision on whether to label a person mentally retarded is largely subjective: In states where retardation has been an issue, experts for the defense and prosecution have presented opposing views of whether a person‘s performance of mundane daily functions is adequate. IQ-test results can vary, depending on the methodology of the person administering the test and the mood of the test taker at the time. What should be the fate of an inmate whose IQ falls below 70 one day and above it on another? Or whose IQ hovers just barely above the cutoff?

There are more than a few of these cases in California. One is that of David Rey Fierro, sentenced to death for the 1985 robbery and shooting death of a merchant outside his store in a small town in Riverside County. During the penalty phase of the trial, the prosecution suggested that as a child Fierro was placed in special-education classes because of ”truancy and discipline problems.“ But Fierro’s attorneys argue that he was put there because he was ”certified as mentally retarded.“ Four separate tests put Fierro‘s IQ anywhere from 66 to 77.

Another case is that of Tracy Cain, who was convicted in 1988 of the robbery and beating death of his elderly neighbors in their home in Oxnard. Court records show that Cain is developmentally disabled and borderline retarded. He is unable to comprehend verbal suggestions and respond. He has trouble writing. Cain has an IQ of 74.

In court last week, the justices offered no guidance as to how such cases should be handled. Little mention was made of the petitioner, Daryl Renard Atkins, who robbed and shot to death a man in Virginia in 1996. Atkins’ IQ has been measured at 59. Instead, the court focused on the question of whether a national consensus opposes the execution of mentally retarded inmates.

When attorney Pamela A. Rumpz, representing the state of Virginia, argued that the states without a death penalty should not be counted as opposed to killing the mentally retarded, O‘Connor retorted testily, ”I can’t imagine you wouldn‘t count those states.“ Rumpz also argued that the move in death-penalty states away from execution of the mentally retarded is merely a momentary shift in public opinion, a ”blip on the radar screen,“ that should not sway the court.

Justice Antonin Scalia, a death-penalty supporter, concurred. ”We have to be very careful here, because there’s no going back if we say this is unconstitutional,“ he said. ”If it turns out there‘s a claim of retardation in almost every case and there are expert witnesses willing to easily say someone is retarded, there’s no way to go back, because no legislation can override a constitutional finding.“ Atkins‘ attorney, James W. Ellis, countered that the states that ban execution of the mentally retarded have not received frivolous claims.

But Scalia persisted. He was the only justice who openly dismissed the contention that mentally retarded people are less culpable and should not be put to death. ”They had to know what they were doing was wrong,“ he said. ”Or they wouldn’t have been competent to stand trial.“ Ellis said the issue is not whether a mentally retarded person can understand the difference between right and wrong. ”A person may have criminal intent,“ Ellis said. ”But because of retardation he has less than a full understanding of what he‘s doing and the consequences. Just as we don’t want to execute those under the age of 16, we don‘t want the death penalty used for the retarded.“

Sara Catania has been selected for a 2002 Crime and Communities Media Fellowship with the Open Society Institute, a New York–based nonprofit dedicated to reforming the criminal-justice system. This story is one in a yearlong series of articles on death row, funded in part by the fellowship.

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