CORY MAPLES is not a sympathetic character. But even lawyers for the state of Alabama, where Mr. Maples sits on death row, acknowledge that “it is hard not to feel a little sorry for a petitioner like . . . Cory Maples, who loses his chance to assert claims in federal court because of his lawyers’ errors.”

And what errors they were.

Mr. Maples was convicted of murdering two people in Alabama in 1995. He has never claimed his innocence but has argued that he should not have been sentenced to death. Among other things, he notes, his lawyers failed to introduce evidence that he was highly intoxicated the night of the murders — a fact that could have undercut the case for capital punishment. He appealed his case in state courts but lost. Typically, defendants are entitled to take their claims to federal court once the state process is exhausted. This is where Mr. Maples’s case went wrong.

A judge’s order denying the last of Mr. Maples’s state appeals was mailed to the office of the inmate’s two appellate lawyers in New York, but the letter was returned, unopened, to the Alabama court clerk because the lawyers had not told the court that they had left the law firm. The clerk’s office did not act on the information; an Alabama attorney who was local counsel also received the judge’s order but ignored it, assuming that the New York lawyers would continue to take the lead.

As a result, Mr. Maples missed a deadline for filing a federal court challenge. He took action as soon as he became aware of the error, but the U.S. Court of Appeals for the 11th Circuit declined to let him proceed. The Supreme Court is scheduled to take up Mr. Maples’s case next month.

Alabama argues that lawyers make mistakes all the time that defendants have to live with. It cites a 1991 Supreme Court case that severely limited a defendant’s ability to overcome a lawyer’s errors, including missed filing deadlines. In our opinion, this decision in Coleman v. Thompson was harsh, bordering on punitive, and the court should rethink its holding.

Mr. Maples’s two lead lawyers did not merely make mistakes; they essentially abandoned their client. The Alabama court clerk’s office, too, shares responsibility for the pitiful series of events. All of this was beyond Mr. Maples’s control. It would offend the essence of fairness to allow a mailroom error to deprive a death row inmate of his last, best chance to avoid execution.