The execution of three inmates has been put on hold, as the Supreme Court intervenes in a case that involves the controversy over the drugs states use to put people to death. The justices cited the sedative midazolam, which has been used in three executions that did not go smoothly.

The Supreme Court's stay is likely to hold until April, when it will hear arguments from three inmates who say that Oklahoma's execution protocol violates the U.S. Constitution.

The court's order did not elaborate on the reasons or debate behind the move:

"Respondents' application for stays of execution of sentences of death presented to Justice Sotomayor and by her referred to the Court is granted and it is hereby ordered that petitioners' executions using midazolam are stayed pending final disposition of this case."

As we reported earlier this month when Oklahoma executed an inmate, states with capital punishment laws have been scrambling to find alternatives to the lethal injection drugs they once used:

"A shortage of the traditional drug, sodium thiopental, forced Oklahoma to begin using pentobarbital in 2010. At the time, a prisoner's attorney argued that pentobarbital, which has been used to euthanize animals, was unsafe and not approved by the Food and Drug Administration."The Oklahoman reports, 'The Corrections Department was forced to use the sedative midazolam on [Clayton] Lockett. Midazolam also was used in two recent problematic executions, one in Ohio and another in Arizona.' "

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