The US Supreme Court will on Monday take up the thorny issue of lethal injections in a bid to determine if this method of executing death-row inmates conforms with the constitution, which forbids cruel and unusual punishment.
The review comes after death penalty opponents have demonstrated that lethal injection can in fact be painful, and amid a rise in questions about whether the death penalty generally has been applied fairly and accurately around the country since it was restored in a 1976 Supreme Court decision.
Conceived without much study in 1977 and used in 98 percent of the most recent 500 executions, lethal injection involves three chemicals: the first one puts the prisoner to sleep, the second paralyzes his muscles and the third stops his heart.
If all goes according to plan, the inmate quickly becomes unconscious and dies within several minutes.
But if the first chemical is not administered properly, the two others become extremely painful.
Several scientific studies and a series of botched executions have shown that that could take place.
In 2004, two prisoners in Kentucky, Ralph Blaze, sentenced to death for the murder of two police officers, and Thomas Bowling, found guilty murdering a couple in the process of stealing their car, argued in court that lethal injection constituted a "cruel and unusual punishment" forbidden by the Eighth Amendment of the US constitution.
They lost their appeal in a circuit court, but judges in other states seized upon similar complaints and backed the death-row inmates.
"The case is not about ending the capital punishment, but it is about ensuring that as long as the states and the federal jurisdictions continue to carry out executions, the method, manner and means of execution comply with the Eighth Amendment," said Elisabeth Semel, director of the Death Penalty Clinic at the University of California-Berkeley School of Law.
"It is not about ensuring the absence of pain. It is about taking reasonable measures to avoid infliction of severe pain."
As far as authorities in Kentucky are concerned, the procedure is not in question because suffering occurs only in case of an error or accident.
But the inmates argued that the procedure is so complex and prison personnel are so inadequately trained that the risk of severe suffering is unacceptably high.
That is why the death-row inmates propose establishing strict criteria for administering the triple injection.
However, their demands cannot be carried out without the participation of doctors and anesthesiologists, and often these specialists refuse to take part in the procedure.
An alternative solution would involve injecting the prisoner with a massive dose of barbiturates.
In that case, death would arrive more slowly, but the inmate would feel nothing.
A decision by the Supreme Court is awaited before July.
In the meantime, across the United States execution chambers are empty in the wake of a de facto moratorium on executions since the high court announced in late September that it would take up the case.
Even earlier, executions had been already suspended in about a dozen states, in part over new information, often DNA analysis-based, that too many prisoners had been sentenced to death on bad evidence or through unjust legal procedures. In December, New Jersey became the first US state in 40 years to abolish the death penalty.
As a result, last year the count of executions stopped at 42, the lowest number of executed prisoners since 1994.
But even without the worries of perverted justice or the Supreme Court's intervention, executions in the United States have been on the wane.
After attaining a peak of 98 in 1999, they dropped to 71 in 2003 and then 53 in 2006.
Meanwhile the worries about faulty convictions seem to have affected jurors, who are now more hesitant to apply the death penalty and often opt for life in prison.
The number of death sentences being meted out, after peaking at 317 in 1996, fell to 276 in 2000 and 110 in 2007.
Even in Texas, which has executed more than 400 people over 25 years, judges have been handing up fewer than 15 death sentences a year since 2003, while in the past the number often surpassed 30 or 40.
However, public opinion polls are consistent and show the same picture: two-thirds of Americans continue to favor capital punishment, and more than 3,200 inmates remain on death row in the United States.