COLUMBIA, S.C. -- Horace Butler keeps a calendar in his cell on death row, carefully marking off the days with the help of a fellow inmate who tells him when it is time to turn to a new month. Nearly a decade after he was sentenced to death for murdering and raping a convenience store clerk, Butler, 31, cannot tell you what or where the Supreme Court is, although his case has made three trips there and back.

But Butler, whose IQ is 61, according to his lawyers, and functions at the level of a 9-year-old, knows that what he calls his " 'peals" are running out.

The Supreme Court ruled against him in March, and Butler is aware the time is quickly approaching when "they set a date" for him to die in the state's electric chair. It would be the state's fourth execution since 1976, when the Supreme Court reaffirmed that the death penalty does not constitute cruel and unusual punishment.

For both sides of the death penalty debate, Butler offers a case study of a system that seems gravely flawed. They see his experience not as an aberration, but as a parable that takes on added importance in light of recent proposals to speed up death row appeals.

To opponents of capital punishment, Butler's case encapsulates everything that is wrong with the way the death penalty is administered in the United States today, and serves as a warning of the dangers of further streamlining the system.

Butler's lawyers say he faces execution because of incompetent representation at his trial by a sincere but bumbling defense lawyer who was paid just $300 and who spent a mere 10 minutes giving the jury evidence of why his client should not be put to death.

They argue that Butler is mentally retarded, something that was never considered by the jury because his trial lawyer never had him tested. And they note that his conviction was secured primarily on the basis of a confession that the Supreme Court has now ruled was illegally obtained, but which the justices in March refused to throw out retroactively.

"This case is a story of how blindly and randomly the death selection process chooses the tiny handful of people for execution out of a far larger number who commit homicide," said David Bruck, one of Butler's lawyers. "Only a handful of the most badly represented, the poorest, the most retarded and the most unlucky are sentenced to die."

To supporters of the death penalty, the fact that Butler is still alive nearly 10 years after the murder is a testament to a system choking on procedure and technicalities, incapable of actually meting out sentences that have been determined to be just.

They point with frustration to the fact that Butler's case has gone through nine rounds of review in the federal and state courts, none of which has voted to overturn his sentence. In the wake of their latest rebuff by the Supreme Court, Butler's lawyers have gone back to state court with yet another legal argument.

"He's had free attorneys now for 10 years," said Charleston County Solicitor Charles Condon, who had just taken office at the time of Butler's trial in 1981. "Every tactic has been tried. It's been litigated now, time and time again."

Pointing to cases like Butler's, Chief Justice William H. Rehnquist and other critics of the way capital crimes are handled have complained that it "verges on the chaotic," with its seemingly endless rounds of eleventh-hour appeals. The average delay between sentence and execution, Rehnquist noted in a speech last month, is nearly eight years.

While most prisoners have every incentive to seek swift review of their cases and win freedom, these critics argue, the goal of death row inmates is simply to stay alive for as long as possible by stringing out their claims of unconstitutional treatment.

Prodded by Rehnquist and others, the Senate and House are now debating proposals to impose strict limits on the use by death row inmates of federal habeas corpus, under which state prisoners go to federal court to claim their constitutional rights were violated.

Opponents of capital punishment, as well as those who may favor the death penalty but see the federal courts as a critical safeguard, contend that the conservative Supreme Court majority has eviscerated the historical right to habeas corpus review.

They argue that such restrictions are dangerous, noting that courts have found violations of constitutional rights in 40 percent of the capital habeas corpus cases they have heard since 1976. And they complain about what they perceive as the fundamental unfairness of a series of recent rulings, including the one in Butler's case, in which the high court has allowed executions to proceed even in the face of such violations.

Butler's case offers ammunition for both sides.

The issue, Bruck said, is whether "you want to sacrifice people who are innocent or who don't deserve the death penalty, so you can execute the Ted Bundys faster. The public has been inundated with the notion that there are so many protections in the legal system that mistakes don't get made. That's not true now, and it will be even less true in the future," if the proposals to cut back on federal court review succeed.

Condon, reflecting on Butler's case, said he has won seven death sentences but discovered, to his chagrin, "They don't get killed. So for all of the energy and the resources we put into prosecuting these cases, the appeals system, I think, makes a mockery of it. To me, one of the safest places to be in South Carolina is on death row."

Butler's journey to death row started on a hot summer night in 1980 on the back roads of Adams Run in South Carolina's low country, outside Charleston. Pamela Lane, an 18-year-old who had moved from Detroit a few months earlier, had finished her second day of work at Dodge's convenience store on Highway 17 and was riding the 15 miles home to her sister's house on her brand-new moped.

Lane left Dodge's about 10 p.m. on July 17. The next day, two couples fishing off a bridge found her fully-clothed body face down in a crab creek. According to the coroner's report, Lane had recently had intercourse and had been shot in the chest with a .22-caliber weapon and thrown from the bridge.

Several weeks later, police jailed Butler on an unrelated assault charge, later dropped. Eugene Frazier, the Charleston County detective who investigated the Lane murder, recalled that he "probably had probable cause" to charge Butler with murder at the time but chose to hold off in order to obtain the "advantage of getting him on your turf and . . .off guard."

Early in the morning on Sept. 1, after Butler's lawyer had left his client, detectives came to question Butler about the Lane murder. During a long night of interrogation, ending at 5:45 a.m., Butler waived his right to remain silent and told differing stories but eventually confessed to killing Lane.

Butler said he was leaving a local club when he saw Lane drive by on her moped. Lane pulled over when he blinked his lights at her, he said, and voluntarily got into his car, drove with him to nearby Hutton Plantation and had sex with him.

Afterwards, Butler said, "She said she was going to cry rape because she was late getting home. . . . So I panicked. I had the gun in my hand and before I realized what had happened, I shot her and she fell to the ground."

Butler's file ended up on the desk of a young prosecutor, Steve Schmutz, with a note from Schmutz's boss, then-County Solicitor Capers Barr. Barr had his doubts that the facts in the case added up to a capital crime, Schmutz said. After investigating, however, Schmutz decided the case involved not only murder, but rape and kidnapping as well, since he thought Butler's story that Lane had voluntarily accompanied him was ludicrous.

Under state law, those two crimes constituted aggravating circumstances that transformed the murder into a capital crime. Schmutz, finding the crime "egregious, sickening really," decided to seek the death penalty, although he did not formally charge Butler with the rape and kidnapping.

At the trial, the main evidence against Butler was his confession, corroborated by Butler's palm print, found on the moped. A friend of Butler's, Larry White, testified that Butler told him he hit Lane with his car and then shot her. A cousin of Butler's testified that Butler gave him a .22 caliber pistol shortly after the incident. The cousin said Horace's father retrieved the gun and the murder weapon was never found.

But there were some missing pieces. For one thing, an FBI agent testified that a Negroid pubic hair found on Lane's blouse was definitely not from Butler. And aside from a bump on the head which the coroner determined occurred before death, and what the prosecution viewed as the inherent incredibility of Butler's story in light of what county solicitor Condon delicately described as the "social circumstances" of the case -- Butler is black, Lane white -- the evidence of rape was tenuous.

Indeed, after Butler was found guilty of murder, and the jury returned to decide whether there were aggravating circumstances to justify the death penalty, the trial judge, C. Anthony Harris, refused to allow the kidnapping claim to go to the jury and initially said he was "extremely dubious if that evidence {of rape} is there."

The lawyer called by Butler's family, W. McAlister "Mackey" Hill, testified later that the judge, off the record, told the lawyers, "You know that rape won't hold up . . . you know damn well somewhere along the line some federal court judge is going to overturn this."

Six years out of law school, Hill had never handled a murder trial before, much less a death penalty case; if Butler had exercised his constitutional right to have a lawyer appointed for him, Hill would not have met the state's qualifications to serve as lead counsel in a death case.

Hill did not have Butler evaluated by a psychological expert, so the jury was not told of his mental retardation, or his clean criminal record, or his impoverished family background as the seventh of 10 children.

"What the jury knew about Horace was what happened on July 17, 1980. They had no context into which to place what happened in Adams Run," said John Blume, one of Butler's current lawyers. "They had no idea of whose life was in their hands."

At one point before trial, asking the coroner why there were no bruises or tearing in the genital area, Hill said, "now bear in mind that you have a big black 23-year-old buck and a 18-year-old girl."

Hill seemed to stake his defense on the hope -- quickly dashed -- that Butler's incriminating confession would be suppressed. And in the second part of the case, in which the jury was was asked to decide between life and death, the sole witness was Butler's elementary school principal.

"There were some situations that he seemed not to quite grasp what was going to happen that a more experienced lawyer would have," the trial judge, Harris, recalled in an interview. "It was a major miscalculation to put so much stock in the confession not being admissible."

The state and federal courts that reviewed Butler's complaints found that Hill's performance met constitutional standards. Hill declined to comment on the case other than to say that he remains convinced that his client is innocent.

Schmutz, the prosecutor at the trial, said he had no idea of the extent of Butler's impairment. "If I would have known Horace Butler was mentally retarded -- if he was -- I would not have sought the death penalty on him," Schmutz said. "I don't think it was my job to go out and find that he was."

By the time Butler's case got to the Supreme Court, where the justices, on Butler's third try, agreed to hear the case, the issue had come down to whether his confession -- the linchpin of the prosecution's case -- should have been thrown out because it was illegally obtained.

In 1988, seven years after Butler's conviction, the Supreme Court ruled in Arizona v. Roberson that once a suspect has said he wants to see a lawyer, the Fifth Amendment right against self-incrimination prohibits police from further questioning, even on an unrelated charge.

The decision had a direct bearing on Butler's case. At the time detectives interrogated him about the Lane murder, he had clearly invoked his right to counsel on the assault charge. Under Roberson, police would have been barred from questioning him, and the confession would have been thrown out.

But the court, in another decision last year, announced that when reviewing state prisoners' habeas corpus claims, it would generally not apply "new rules" of constitutional law that states could not have been expected to know at the time the case was originally decided.

In Butler's case in March, the court, splitting 5 to 4, said its ruling in Roberson constituted just such a new rule and should not be applied retroactively. Justice William J. Brennan Jr. said in a bitter dissent that the decision "strips state prisoners of virtually any meaningful federal review" of their cases and allows prisoners to be executed "because state courts were reasonable, even though wrong."

In an hour-long interview at the Broad River Correctional Institution, where he spends his days watching soap operas and playing poker with some of the other 45 men on South Carolina's death row, Butler denied killing Lane.

He said his friend White had asked his help in moving the moped, and claimed he was coerced into making an untrue confession.

Butler, who has complained of hearing voices and has been involuntarily committed to state psychiatric facilities five times while in prison, seemed to have little grasp of his case. Polite and passive, he could not name the president of the United States or explain the meaning of mentally retarded. Told that mentally retarded people found it harder than others to learn, Butler, who started first grade at age 12 and dropped out of the third grade four years later, said: "So if I finish school, I wouldn't be retarded?"

South Carolina's senior senator, Strom Thurmond (R), is one of the sponsors of legislation approved by the Senate -- and now bogged down along with other provisions of the crime bill -- designed to speed along cases like Butler's.

"Families of victims are forced to suffer, year after year, while murderers sit on death row . . .," said Thurmond. "Law-abiding citizens are justifiably fed up with death row inmates using procedural loopholes and unwarranted judicial delay to their benefit."

By imposing strict deadlines on federal court actions, the measure would effectively abolish the state version of habeas corpus, which allows state prisoners the chance to have their convictions reviewed in state courts once they have lost the first found of appeals.

Death row prisoners would have to file their petitions for review in federal court within 60 days after the conviction is upheld on appeal in state court. And they would be barred from filing a second habeas petition unless the federal appeals court granted special permission.

The decision that resulted in the Roberson ruling not being applied retroactively in Butler's case would also be modified, and states would be required to appoint competent counsel to represent death row prisoners in their federal claims.

Bruck and Blume said such limits would barely give them enough time to review the trial transcript, much less ferret out errors at trial.

"What harm accrued to the people of South Carolina" from the delays in Butler's case, asked Scharlette Holdman, an investigator who works with Blume. "Horace Butler was safely locked on death row. . . . The harm truly is irreparable when we execute people because of an abritrarily imposed time limit on fairness."

THE BUTLER CASE: A CHRONOLOGY

July 17, 1980: Pamela Lane murdered.

Jan. 26, 1981: Horace Butler sentenced to death for Lane's murder.

Feb. 22, 1982: South Carolina Supreme Court upholds Butler's conviction and sentence.

Oct. 12, 1982: U.S. Supreme Court refuses to review Butler's case.

Oct. 15, 1982: Butler files application for new trial in state court, claiming ineffective assistance of counsel at trial and other violations of constitutional rights.

April 1, 1983: State court holds hearing on Butler's claim of ineffective assistance of counsel at trial.

Jan. 28, 1984: Request for new trial denied.

Aug. 27, 1985: State supreme court rejects Butler's claim of ineffective assistance of counsel.

Jan. 26, 1986: U.S. Supreme Court refuses to review Butler's case.

May 14, 1986: Butler files petition for writ of habeas corpus in federal court claiming ineffective assistance of counsel and other constitutional violations, and arguing that police should not have questioned him about murder once he had invoked his right to counsel on the separate assault charge.

March 9, 1987: U.S. Magistrate rejects Butler's claims.

June 9, 1987: U.S. District Court grants summary judgment to state, rejecting Butler's claims.

July 15, 1987: Butler appeals to 4th U.S. Circuit Court of Appeals in Richmond.

May 6, 1988: 4th Circuit rejects Butler's claims.

June 15, 1988: 4th Circuit denies rehearing.

June 15, 1988: U.S. Supreme Court rules in Roberson v. Arizona, that police cannot question suspects about any crime once they have invoked their right to counsel.

June 16, 1988: Butler asks appeals court to reconsider case in light of Roberson.

Dec. 2, 1988: Appeals court panel denies rehearing and full court rejects request for rehearing, voting 6-5.

Feb. 24, 1989: Butler asks U.S. Supreme Court to hear case.

May 1, 1989: Supreme Court agrees to review case to decide whether Roberson should be applied retroactively.

March 5, 1990: Supreme Court, voting 5-4, refuses to apply Roberson retroactively to grant Butler a new trial.

April 23, 1990: Supreme Court denies petition for rehearing.

May 4, 1990: State asks state supreme court to set execution date.

May 8, 1990: Butler asks state supreme court to stay execution and hear claim that trial judge violated his constitutional right by warning him of consequences of failing to testify.

May 31, 1990: State supreme court hears Butler case.