The U.S. Supreme Court rejected an appeal Monday from a 76-year-old convicted killer who argued that he was too old and feeble to be executed.

The ruling cleared the way for Clarence Ray Allen — legally blind, nearly deaf and in a wheelchair — to be executed by injection early Tuesday for a triple murder he ordered from behind bars to silence witnesses to another killing.

Allen, whose birthday was Monday, stood to become the oldest person executed in California — and the second-oldest put to death nationally — since the Supreme Court allowed capital punishment to resume in 1976.

He raised two claims never before endorsed by the high court: that executing a frail old man would violate the U.S. Constitution's ban on cruel and unusual punishment, and that the 23 years he spent on death row were unconstitutionally cruel as well.

The high court rejected his requests for a stay of execution, about 10 hours before he was to be put to death.

On one of the orders, Justice Stephen Breyer filed a dissent, saying: "Petitioner is 76 years old, blind, suffers from diabetes and is confined to a wheelchair, and has been on death row for 23 years. I believe that in the circumstances he raises a significant question as to whether his execution would constitute cruel and unusual punishment. I would grant the application for stay."

The Supreme Court has never set an upper age limit for executions or created an exception for physical infirmity.

Gov. Arnold Schwarzenegger, the California Supreme Court and a federal appeals court previously refused to spare Allen's life.

Allen went to prison for having his teenage son's 17-year-old girlfriend murdered for fear she would tell police about a grocery-store burglary. While behind bars, he tried to have witnesses in the case wiped out, prosecutors said. He was sentenced to death in 1982 for hiring a hit man who killed a witness and two bystanders.

Allen's heart stopped in September, but doctors revived him and returned him to San Quentin Prison's death row.

"These infirmities are not simply the result of the passage of time or of old age, as some would suggest, but result from prison authorities' deliberate neglect of his medical needs while in the state's custody," said Annette Carnegie, one of Allen's attorneys.

Before Allen, the oldest person executed in California since the reinstatement of the death penalty was a 61-year-old man put to death last January. He had spent 21 years on death row.

Last month in Mississippi, John B. Nixon, 77, became the oldest person executed in the United States since capital punishment resumed. He did not pursue an appeal based on his age.

Over the years, some justices on the Supreme Court have expressed interest in deciding whether a long stay on death row can be unconstitutionally cruel.

In 2002, Breyer said in the case of a Florida inmate who spent 27 years in prison: "It is fairly asked whether such punishment is both unusual and cruel."

Justice Clarence Thomas disagreed, writing that the inmate "could long ago have ended his anxieties and uncertainties by submitting to what the people of Florida have deemed him to deserve: execution."