US Supreme Court declines to halt execution of child killer

The US Supreme Court declined Thursday to stop the execution of a convicted child rapist and killer, rejecting concerns about the inmate potentially feeling sensations equivalent to being "burned alive".

But the high court's decision was countered with a blistering dissent from Justice Sonia Sotomayor, who questioned whether Billy Ray Irick's planned execution would be too painful and whether allowing it to proceed required accepting "barbarism".

The high court's rejection of Irick's appeal likely means his execution will move forward Thursday evening in the state of Tennessee.

The 59-year-old was convicted in 1986 of raping and killing seven-year-old Paula Dyer. His lawyers have argued Irick has a history of severe mental illness.

In an appeal to the Supreme Court, Irick's lawyers challenged Tennessee's lethal injection protocol, which included the use of the sedative midazolam. Other states have also used the drug for executions with mixed results.

Supreme Court Justice Elena Kagan denied the appeal without comment.

Justice Sonia Sotomayor, citing lower court testimony about the potential risks of midazolam executions, dissented.

Medical experts warned the drug may not be strong enough to keep a prisoner unconscious once he starts to feel pain.

If Irick were to awaken, a paralytic used as the second drug in Tennessee's lethal injection would prevent him from alerting officials that he can feel pain, Sotomayor noted.

"Medical experts explained in painstaking detail how the three-drug cocktail Tennessee plans to inject into Irick's veins will cause him to experience sensations of drowning, suffocating, and being burned alive from the inside out," Sotomayor wrote.

"If the law permits this execution to go forward in spite of the horrific final minutes that Irick may well experience, then we have stopped being a civilized nation and accepted barbarism."