Page:Glossip v. Gross.pdf/17

 Cite as: 576 U. S. ____ (2015)

13

Opinion of the Court

implemented, and in fact significantly reduce[s] a substantial risk of severe pain.” Id., at 52. The controlling opinion summarized the requirements of an Eighth Amendment method-of-execution claim as follows: “A stay of execution may not be granted on grounds such as those asserted here unless the condemned prisoner establishes that the State’s lethal injection protocol creates a demonstrated risk of severe pain. [And] [h]e must show that the risk is substantial when compared to the known and available alternatives.” Id., at 61. The preliminary injunction posture of the present case thus requires petitioners to establish a likelihood that they can establish both that Oklahoma’s lethal injection protocol creates a demonstrated risk of severe pain and that the risk is substantial when compared to the known and available alternatives. The challenge in Baze failed both because the Kentucky inmates did not show that the risks they identified were substantial and imminent, id., at 56, and because they did not establish the existence of a known and available alternative method of execution that would entail a significantly less severe risk, id., at 57–60. Petitioners’ arguments here fail for similar reasons. First, petitioners have not proved that any risk posed by midazolam is substantial when compared to known and available alternative methods of execution. Second, they have failed to establish that the District Court committed clear error when it found that the use of midazolam will not result in severe pain and suffering. We address each reason in turn. IV Our first ground for affirmance is based on petitioners’ failure to satisfy their burden of establishing that any risk of harm was substantial when compared to a known and available alternative method of execution. In their amended complaint, petitioners proffered that the State