Seven of the 12 jurors who convicted Ronald B. Smith in the murder of a convenience store clerk voted to spare his life. When the case reached the Supreme Court, four of the eight justices voted to stay his execution.

The arithmetic of capital punishment can seem curious. Mr. Smith was executed Thursday night.

Mr. Smith was convicted of murdering the clerk in 1994 in Huntsville, Ala. The jury recommended life without parole, but the trial judge overrode that determination, sentencing Mr. Smith to death.

Alabama is the only state that allows such overrides. It is a good bet that the Supreme Court will soon weigh the constitutionality of the practice.

That will be too late for Mr. Smith, who came up one vote short on Thursday night, illuminating a lethal gap in the Supreme Court’s internal practices. It takes four votes to put a case on the court’s docket, but it takes five to stop an execution.