California's oldest death row inmate — a 75-year-old who is legally blind and nearly deaf — is asking the U.S. Supreme Court to do something it has never done before: block an execution because of the condemned man's advanced age and infirmity.

Clarence Ray Allen's attorneys contend that executing a feeble old man amounts to cruel and unusual punishment banned by the U.S. Constitution.

Gov. Arnold Schwarzenegger on Friday denied Allen clemency. He is set to die by injection Tuesday for ordering three slayings while behind bars for another murder. He has been on death row for more than 23 years.

Allen, who turns 76 on the eve of his execution, would be the second-oldest person executed in the United States since the Supreme Court allowed capital punishment to resume in 1976. He often uses a wheelchair and had to be resuscitated after suffering a heart attack last year at San Quentin Prison.