Washington (CNN) The U.S. Supreme Court on Monday upheld the use of a controversial drug for lethal injection in executions, but opened a larger question about capital punishment when two justices in the minority newly questioned whether the death penalty violates the Constitution.

The ruling in the execution drugs case was 5-4 with Justice Samuel Alito writing for the majority, along with Chief Justice John Roberts, Justices Antonin Scalia, Anthony Kennedy and Clarence Thomas.

"The prisoners failed to identify a known and available alternative method of execution that entails a lesser risk of pain, a requirement of all Eighth Amendment method-of-execution claims," Alito wrote. "Second, the District Court did not establish that Oklahoma's use of a massive dose of midazolam in its execution protocol entails a substantial risk of severe pain."

The main dissent was written Justice Sonia Sotomayor, but in a separate dissent, Justice Stephen Breyer raised the question of whether the the court should revisit the death penalty. He was joined by Justice Ruth Bader Ginsburg.



"I would ask for a full briefing on a more basic question: whether the death penalty violates the constitution," Breyer wrote.

Breyer was answered directly by Justice Antonin Scalia, who wrote a concurring opinion specifically to refute his colleague.

"Welcome to Groundhog Day," Scalia wrote, suggesting he has heard these arguments before.

"We federal judges live in a world apart from the vast majority of Americans," Scalia wrote in reference to Breyer's suggestion that data does not show a deterrent effect from the death penalty. "After work, we retire to homes in placid suburbia or to high-rise co-ops with guards at the door. We are not confronted with the threat of violence that is ever present in many Americans' everyday lives."

In an extremely rare occurrence, four separate justices read opinions from the bench. Court watchers said the public debate reflected something new at the Supreme Court.

"Separate from the questions the Court decided in this case, the fight between Justices Breyer and Scalia over the constitutionality of capital punishment itself is remarkable in any number of respects," said Steve Vladeck, a law professor at American University and CNN contributor. "Although previous Justices—including Justices Blackmun and Stevens—have objected to the death penalty, they did so late in their careers, at a point at which it was more a moral statement than a legal one. Here, in contrast, the Court's two senior progressive Justices, who don't seem to be going anywhere anytime soon, have opened the door to frontal assaults on the death penalty—and, in doing so, have provoked the ire, sarcasm, and perhaps fear, of the Court's conservative lion."

The Supreme Court re-instated the death penalty in 1976 after having suspended it earlier in the 1970s. Capital punishment is now used in 31 states and by the federal government.

In the case decided Monday, three death row inmates -- Richard E. Glossip, John M. Grant and Benjamin R. Cole -- brought the challenge arguing that the drug midazolam violates the 8th Amendment's ban on cruel and unusual punishment because it fails to generate "a deep, coma like unconsciousness."

Another plaintiff in the case, Charles F. Warner, was put to death , apparently without incident, before the Court agreed to take up the case.

Oklahoma uses an intravenous injection of midazolam to cause unconsciousness and follows it with a paralytic and then a third drug meant to serve as a heart-stopping agent.

But Robin C. Konrad, a lawyer for the prisoners, told the justices that midazolam "can never maintain the deep coma-like unconsciousness that is necessary to prevent a prisoner" from feeling the painful effects of the other two drugs in the protocol.

Six states - Alabama, Arizona, Florida, Louisiana, Oklahoma and Virginia - have midazolam as an option in for use in lethal injections in their protocols.

The Supreme Court hearing revealed a deep tension on the part of some of the conservatives on the bench who expressed concern that the opponents to the death penalty are making it very difficult for the states to carry out executions using lethal doses of drugs.

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"Let's be honest about what's going on here," said Justice Samuel Alito. He suggested that executions could be carried out painlessly but those who oppose the death penalty are conducting "what amounts to a guerrilla war" consisting of efforts to make it impossible for the states to "obtain drugs that could be used to carry out capital punishment with little, if any pain."

But the liberals, led by Justice Sonia Sotomayor questioned the use of the drug as well as the state's case.

In 2008, the Supreme Court upheld Kentucky's lethal injection protocol, but that case concerned a different combination of drugs that is no longer being used.

In court papers, Patrick Wyrick, the Solicitor General of Oklahoma said the state has improved its protocol since Lockett's death and that the current protocol "does not present a substantial risk of severe pain and cannot be considered cruel."

He described the crimes committed by the inmates including the fact that Glossip "hired his coworker to kill their employer by beating him to death with a baseball bat," and that Benjamin Cole "murdered his nine-month old daughter by snapping her spine in half."

In court, he told the justices that a lower court found that a 500 milligram dose of midazolam would "with near certainty, render these petitioners unconscious and unable to feel pain."

The case comes when 70% of Americans say they don't consider the death penalty itself to be "cruel and unusual punishment," according to a recent CNN/ORC poll.