The Supreme Court granted a last-minute stay of execution last night to a Texas death-row inmate who says he is innocent of the murder of which he was convicted 23 years ago, setting the stage for another high-profile debate at the court over alleged flaws in the U.S. capital punishment system.

In a brief order issued about 10 minutes before officials were to administer a lethal injection to Delma Banks Jr., the justices said that he should be kept alive at least long enough for them to consider his request for a full-scale hearing on claims that his 1980 trial in Bowie County, Tex., was marred by prosecutorial misconduct, ineffective defense counsel and racially discriminatory jury selection.

Banks, an African American, was convicted of killing a white teenager by an all-white jury. If his execution had proceeded last night, he would have been the 300th person put to death in Texas since the state resumed executions in 1982.

It was unclear when the court might meet to consider Banks' petition. Its next scheduled closed-door conference is March 21. However, the stay may be a favorable sign for Banks because it required the votes of at least five justices, and a decision to hear his case could be made with the assent of just four justices.

Consistent with growing public concern over the possibility of wrongful death sentences, the court has shown interest recently in the issues raised by Banks' appeal, though its rulings have not always come out the way death penalty opponents would have liked.

The court ordered a lower court review of another Texas man's death sentence last month, ruling that a case could be made that jury selection at his trial was racially biased; last year, it abolished capital punishment for the mentally retarded. But also last year, the court rebuffed an effort to seek abolition of the death penalty for juveniles and let Virginia proceed with the execution of a murderer who had been represented at trial by the murder victim's former lawyer.

"Delma Banks Jr,. who has maintained his innocence from the beginning, found justice in the courts today, and we are hopeful that this delay will allow a meaningful review of the serious claims in his case," Banks' lawyer, George Kendall of the NAACP Legal Defense and Education Fund, said in a prepared statement. "The court's decision to stay the execution in order to potentially hear the significant claims put before it demonstrates that our tribunals will not turn a blind eye to egregious miscarriages of justice."

Bobby Lockhart, district attorney of Bowie County, said, "Factually, [Banks] was guilty, and legally the jury found him guilty. As to the death penalty, that's up to the Supreme Court. I think that the Supreme court will review the case and find that he was guilty, and I think there's no way the stay [of execution] will be extended beyond 30 days."

Banks' case has attracted attention in part because of the supporters who have rallied to his cause, including former FBI director William S. Sessions and two former federal appeals court judges.

In a brief submitted to the Supreme Court in support of Banks' request for a stay, Sessions and his colleagues said that the Banks case is tainted by "uncured constitutional errors" that are "typical of those that have undermined public confidence in the fairness of our capital punishment system."

Banks, then 21, was convicted in 1980 of shooting his co-worker Richard Wayne Whitehead, 16, to death with a .25-caliber handgun.

Banks' lawyers argue that prosecutors wrongfully suppressed evidence that one of their key witnesses, who has since recanted, lied on the stand. Banks' attorneys also argue that his inexperienced defense lawyers offered little evidence to counter prosecutors' claims that Banks deserved the death penalty, even though he had no previous criminal record.

Prosecutors kept African Americans off the jury, they contend, producing the all-white panel that convicted Banks and sentenced him to death in the course of two days of legal proceedings.

No physical evidence linked Banks to the crime. But Banks was the last person seen with Whitehead, and prosecutors said their case against him is strong. Last week, the New Orleans-based U.S. Court of Appeals for the 5th Circuit, reversing a federal district judge's ruling in favor of Banks, permitted his execution to proceed, on the grounds that the alleged flaws in his trial were not substantial enough to have changed the outcome.

The Texas Court of Criminal Appeals this week refused to block Banks' execution, and the Texas Board of Pardons and Paroles would not hear his plea because it was filed too late.

Because of the prolonged appeals process in his case, Banks has been on death row while Texas conducted 299 executions, the most of any state since the Supreme Court permitted states to resume capital punishment in 1976.

Delma Banks Jr., convicted of murder in 1980.In Huntsville, Tex., Banks's daughter, Dakinya Jefferson, left, and ex-wife, Demetra Jefferson Wysinger, celebrate.