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(CNN) -- A botched lethal injection in Oklahoma has catapulted the issue of U.S. capital punishment back into the international spotlight, raising new questions about the drugs being used and the constitutional protection against cruel and unusual punishment.
"We have a fundamental standard in this country that even when the death penalty is justified, it must be carried out humanely -- and I think everyone would recognize that this case fell short of that standard," White House spokesman Jay Carney said Wednesday.
What went wrong Tuesday in Oklahoma "will not only cause officials in that state to review carefully their execution procedures and methods," said Richard W. Garnett, a former Supreme Court law clerk who now teaches criminal and constitutional law at the University of Notre Dame, "it will also almost prompt many Americans across the country to rethink the wisdom, and the morality, of capital punishment."
"The Constitution allows capital punishment in some cases, and so the decision whether to use it or abandon it, and the moral responsibility for its use and misuse, are in our hands," he said.
Precisely what happened during the execution of convicted murderer and rapist Clayton Lockett remains unclear. Witnesses described the man convulsing and writhing on the gurney, as well as struggling to speak, before officials blocked the witnesses' view.
It was the state's first time using a new, three-drug cocktail for an execution.
Oklahoma halted the execution of another convicted murderer and rapist, Charles Warner, which was scheduled for later in the day.
Thirty-two U.S. states have the death penalty, as does the U.S. government and the U.S. military. Since 2009, three states -- New Mexico, Connecticut, and Maryland -- have voted to abolish it.
States that have capital punishment have been forced to find new drugs to use since European-based manufacturers banned U.S. prisons from using theirs for executions. One of those manufacturers is the Danish company Lundbeck, maker of pentobarbital.
Carney, speaking to reporters at a daily briefing, said he had not discussed the Oklahoma case with President Barack Obama.
"He has long said that while the evidence suggests that the death penalty does little to deter crime, he believes there are some crimes that are so heinous that the death penalty is merited." The crimes committed by the two men in Oklahoma "are indisputably horrific and heinous," Carney said.
'There was chaos'
Lockett lived for 43 minutes after being administered the first drug, CNN affiliate KFOR reported. He got out the words "Man," "I'm not," and "something's wrong," reporter Courtney Francisco of KFOR said. Then the blinds were closed.
Other reporters, including Cary Aspinwall of the Tulsa World newspaper, also said Lockett was still alive and lifted his head while prison officials lowered the blinds so onlookers couldn't see what was going on.
Dean Sanderford, Lockett's attorney, said his client's body "started to twitch," and then "the convulsing got worse. It looked like his whole upper body was trying to lift off the gurney. For a minute, there was chaos."
Sanderford said guards ordered him out of the witness area, and he was never told what had happened to Lockett, who was convicted in 2000 of first-degree murder, rape, kidnapping and robbery.
After administering the first drug, "We began pushing the second and third drugs in the protocol," said Oklahoma Department of Corrections Director Robert Patton. "There was some concern at that time that the drugs were not having the effect. So the doctor observed the line and determined that the line had blown." He said that Lockett's vein had "exploded."
The execution process was halted, but Lockett died of a heart attack, Patton said.
"I notified the attorney general's office, the governor's office of my intent to stop the execution and requested a stay for 14 days," said Patton.
Gov. Mary Fallin issued a statement saying that "execution officials said Lockett remained unconscious after the lethal injection drugs were administered."
Another state, another botched execution
Earlier this year, a convicted murderer and rapist in Ohio, Dennis McGuire, appeared to gasp and convulse for at least 10 minutes before dying from the drug cocktail used in his execution.
Ohio used the sedative midazolam and the painkiller hydromorphone in McGuire's January execution, the state said.
Louisiana announced later that month that it would use the same two-drug cocktail.
Oklahoma had announced the drugs it planned to use: midazolam; vecuronium bromide to stop respiration; and potassium chloride to stop the heart. "Two intravenous lines are inserted, one in each arm. The drugs are injected by hand-held syringes simultaneously into the two intravenous lines. The sequence is in the order that the drugs are listed above. Three executioners are utilized, with each one injecting one of the drugs."
The execution was the first time Oklahoma had used midazolam as the first element in its three-drug cocktail. The drug is generally used for children "before medical procedures or before anesthesia for surgery to cause drowsiness, relieve anxiety, and prevent any memory of the event," the U.S. National Library of Medicine says. "It works by slowing activity in the brain to allow relaxation and sleep."
The drug "may cause serious or life-threatening breathing problems," so a child should only receive it "in a hospital or doctor's office that has the equipment that is needed to monitor his or her heart and lungs and to provide life-saving medical treatment quickly if his or her breathing slows or stops."
Cruel and unusual?
The question for courts is whether using such drugs in executions constitutes "cruel and unusual" punishment, in violation of the Eighth Amendment to the U.S. Constitution.
After his execution, McGuire's family filed a lawsuit seeking an injunction of the execution protocol the state used.
"The lawsuit alleges that when Mr. McGuire's Ohio execution was carried out on January 16th, he did endure frequent episodes of air hunger and suffocation, as predicted," the office of the family's attorney Richard Schulte said in a statement. "Following administration of the execution protocol, the decedent experienced 'repeated cycles of snorting, gurgling and arching his back, appearing to writhe in pain,' and 'looked and sounded as though he was suffocating.' This continued for 19 minutes."
In Oklahoma, attorneys for both Lockett and Warner have been engaged in a court fight over the drugs used in the state's executions.
They'd initially challenged the state Department of Corrections' unwillingness to divulge which drugs would be used. The department finally disclosed the substances.
Lockett and Warner also took issue with the state's so-called secrecy provision forbidding it from disclosing the identities of anyone involved in the execution process or suppliers of any drugs or medical equipment. The Oklahoma Supreme Court rejected that complaint, saying such secrecy does not prevent the prisoners from challenging their executions as unconstitutional.
After Lockett's execution, Adam Leathers, co-chairman of the Oklahoma Coalition to Abolish the Death Penalty, accused the state of having "tortured a human being in an unconstitutional experimental act of evil."
"Medical and legal experts from around the country had repeatedly warned Oklahoma's governor, courts and Department of Corrections about the likelihood that the protocol intended for use ... would be highly problematic," said Deborah Denno, death penalty expert at Fordham Law School.
"This botch was foreseeable and the state (was) ill prepared to deal with the circumstances despite knowing that the entire world was watching. Lethal injection botches have existed for decades but never have they been riskier or more irresponsible than they are in 2014. This outcome is a disgrace," Denno said.
Amnesty International USA called the botched execution "one of the starkest examples yet of why the death penalty must be abolished."w
"Last night the state of Oklahoma proved that justice can never be carried out from a death chamber," Executive Director Steven W. Hawkins said in a statement.
The Oklahoma attorney general's office is "gathering information on what happened in order to evaluate," said spokeswoman Dianne Clay.
Fallin ordered an independent review of the state's execution procedures and issued an executive order granting a two-week delay in executions.
"I believe the legal process worked. I believe the death penalty is an appropriate response and punishment to those who commit heinous crimes against their fellow men and women. However, I also believe the state needs to be certain of its protocols and its procedures for executions and that they work," she told reporters Wednesday.
Fallin gave no deadline for the review, which will be led by Department of Public Safety Commissioner Michael Thompson. If it is not done within the 14-day period, the governor said she would issue an additional stay for Warner.
Lockett's attorney slammed the announcement and called for a "truly" independent investigation.
"The DPS is a state agency, and its Commissioner reports to the Governor. As such, the review proposed by Governor Fallin would not be conducted by a neutral, independent entity.
"In order to understand exactly what went wrong in last night's horrific execution, and restore any confidence in the execution process, the death of Clayton Lockett must be investigated by a truly independent organization, not a state employee or agency," Dean Sanderford said in a statement.
Lockett was convicted in 2000 of a bevy of crimes that left Stephanie Nieman dead and two people injured.
Nieman's parents released a statement Tuesday prior to Lockett's scheduled execution.
"God blessed us with our precious daughter, Stephanie for 19 years," it read. "She was the joy of our life. We are thankful this day has finally arrived and justice will finally be served."
Warner, who now awaits execution, was convicted in 2003 for the first-degree rape and murder six years earlier of his then-girlfriend's 11-month-old daughter, Adrianna Waller.
His attorney, Madeline Cohen, said further legal action can be expected given that "something went horribly awry" in Lockett's execution Tuesday.
"Oklahoma cannot carry out further executions until there's transparency in this process," Cohen said. "... Oklahoma needs to take a step back."
In a CNN/ORC poll earlier this year, 50% of Americans said the penalty for murder in general should be death, while 45% said it should be a life sentence. The survey's sampling error made that a statistical tie. Fifty-six percent of men supported the death penalty for murder in general, while 45% of women did.
A Gallup poll last year found 62% of Americans believe the death penalty is morally acceptable, while half as many, 31%, consider it morally wrong.
CNN's Dana Ford, Eliott C. McLaughlin and Ross Levitt contributed to this report.