Several bishops in the U.S. have welcomed the Supreme Court's decision to re-examine death penalty protocols, and have called for the abolition of the death penalty.

"We pray that the court's review of these protocols will lead to the recognition that institutionalized practices of violence against any person erode reverence for the sanctity of every human life. Capital punishment must end," Cardinal Sean O'Malley of Boston, who chairs the U.S. bishops' pro-life activities committee, said Jan. 27.

Archbishop Thomas Wenski of Miami, who chairs the committee on domestic justice, said recent executions have shown "how the use of the death penalty devalues human life and diminishes respect for human dignity."

The U.S. Supreme Court has announced it will consider the case Glossip v. Gross, brought by three Oklahoma death row inmates, Richard Glossip, John Grant, and Benjamin Cole.

The inmates' lawsuit asks the court to reject the three-drug protocol used in Oklahoma executions, saying it can cause extreme pain that violates constitutional bans on cruel and unusual punishment. Among the drugs in the cocktail is midazolam, a sedative.

The case was filed in response to the botched April 2014 execution of Clayton Lockett in Oklahoma, which took more than 40 minutes. Although sedated, his body writhed and he breathed heavily as he was being killed. He eventually died of a heart attack.

Oklahoma officials said Lockett's vein failed during the execution, which prevented the lethal drugs from working as intended. Other reports said officials failed to deliver the intravenous drug properly.

Following Lockett's execution, Oklahoma governor Mary Fallin had issued a temporary stay of the exeuction of Charles Warner. The federal government also investigated the execution practices.

Warner, who was one of the inmates listed as a plaintiff in the Supreme Court case, was  executed in mid-January. Supreme Court justices, by a vote of 5-4, voted not to stay the execution of Warner, who was a convicted child rapist and murderer.

Glossip, was scheduled to be executed Jan. 29.

However, the Supreme Court granted a stay of execution Jan. 28 to all three living inmates who are plaintiffs in the case, writing that "it is hereby ordered that petitioners' executions using midazolam are stayed pending final disposition of this case."

It is disputed whether or not midazolam produces a deep enough sleep for the inmate to experience less pain when the other two drugs of the cocktail are administered.

The Supreme Court failed to stay not only Warner's Jan. 15 execution, but also the Jan. 27 execution of Warren Hill in Georgia. Hill's execution was being challenged on grounds of intellectual disability.

Catholic leaders have criticized the continued use of capital punishment.
Cardinal O'Malley said that society can protect itself "in ways other than the use of the death penalty."

"We bishops continue to say, we cannot teach killing is wrong by killing," Archbishop Wenski added.

The inmates' attorney, Dale Baich, characterized Oklahoma's new drug protocols as "novel and experimental."

Oklahoma Attorney General Scott Pruitt has defended the state's use of lethal injection, saying its constitutionality has been affirmed by two federal courts. Defending the constitutionality of the execution procedure will preserve the Oklahoma Department of Correction's ability "to proceed with the sentences that were given to each inmate by a jury of their peers," he said Jan. 23.

The Supreme Court is expected to hear the inmates' case in April.

States that use lethal injections have faced increasing difficulty in obtaining the drugs used, mainly because the drugs' manufacturers refuse to sell them for use in lethal executions, NBC News reports.

In May 2014, Ohio's botched execution of inmate Dennis McGuire, which also used midazolam, also prompted calls to revisit the death penalty.

Several U.S. states have moved away from capital punishment in recent years. In total, 18 states have abolished capital punishment.

The U.S. bishops' conference cited Pope Francis' October 2014 call to abolish the death penalty "in all its forms." The conference is working with state Catholic conferences, the Catholic Mobilizing Network, as well as with other groups, to work to abolish the death penalty in the U.S. In 2005, the bishops launched the Campaign to End the Use of the Death Penalty.