U.S. Supreme Court justices Wednesday without a noted dissent delayed the scheduled execution of three Oklahoma death-row inmates, whose case the justices will hear in late April.

On Monday, Oklahoma Attorney General Scott Pruitt asked for the stays of execution of three death-row inmates until a resolution in U.S. Supreme Court on Glossip v. Gross, a petition filed last week.

Richard E. Glossip’s execution was scheduled for Jan. 29, John M. Grant’s for Feb. 19 and Benjamin R. Cole’s for March 5.

They were scheduled to be executed by the Oklahoma Department of Corrections using a three-drug protocol of midazolam hydrochloride, rocuronium bromide and potassium chloride.

The executions were put on hold, but only so far as the state would use the sedative midazolam in the procedure. The order leaves Oklahoma with the option of trying to develop a new lethal-drug protocol that could free it to resume executions.

Brady Henderson, legal director for the ACLU’s Oklahoma chapter, said the death penalty is the gravest exercise of government power over its own citizens.

“Both the U.S. Supreme Court’s decision to review Oklahoma’s protocols and Attorney General Pruitt’s request for stays acknowledge that it must be carefully scrutinized and should never be done in a slipshod fashion,” Henderson said.

Last year, the execution of Clayton Lockett, which relied on an experimental lethal injection protocol, took more than 40 minutes to cause death.

“When the death penalty is imposed, there is no going back, and that is precisely why future Oklahoma executions must be stayed while the Supreme Court reviews Oklahoma’s deeply-flawed machinery of death,” Henderson said.

On Monday, Pruitt said it is important the state act in order to best serve the interests of the victims of these horrific crimes and the state’s obligation to ensure justice in each and every case.

“The families of the victims in these three cases have waited a combined 48 years for the sentences of these heinous crimes to be carried out,” Pruitt said on Monday.

Two federal courts previously held Oklahoma’s current protocol as constitutional.

“We believe the United States Supreme Court will find the same,” Pruitt said. “We thus support stays until a decision in the state’s favor is final or until viable alternative drugs can be obtained.”