Page:Glossip v. Gross.pdf/21

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

17

Opinion of the Court

Second, petitioners bear the burden of persuasion on this issue. Baze, supra, at 41. Although petitioners expend great effort attacking peripheral aspects of Dr. Evans’ testimony, they make little attempt to prove what is critical, i.e., that the evidence they presented to the District Court establishes that the use of midazolam is sure or very likely to result in needless suffering. Third, numerous courts have concluded that the use of midazolam as the first drug in a three-drug protocol is likely to render an inmate insensate to pain that might result from administration of the paralytic agent and potassium chloride. See, e.g., 776 F. 3d 721 (case below affirming the District Court); Chavez v. Florida SP Warden, 742 F. 3d 1267 (affirming the District Court); Banks v. State, 150 So. 3d 797 (Fla. 2014) (affirming the lower court); Howell v. State, 133 So. 3d 511 (Fla. 2014) (same); Muhammad v. State, 132 So. 3d 176 (Fla. 2013) (same). (It is noteworthy that one or both of the two key witnesses in this case—Dr. Lubarsky for petitioners and Dr. Evans for respondents—were witnesses in the Chavez, Howell, and Muhammad cases.) “Where an intermediate court reviews, and affirms, a trial court’s factual findings, this Court will not ‘lightly overturn’ the concurrent findings of the two lower courts.” Easley v. Cromartie, 532 U. S. 234, 242 (2001). Our review is even more deferential where, as here, multiple trial courts have reached the same finding, and multiple appellate courts have affirmed those findings. Cf. Exxon Co., U. S. A. v. Sofec, Inc., 517 U. S. 830, 841 (1996) (explaining that this Court “ ‘cannot undertake to review concurrent findings of fact by two courts below in the absence of a very obvious and exceptional showing of error’ ” (quoting Graver Tank & Mfg. Co. v. Linde Air Products Co., 336 U. S. 271, 275 (1949))). Fourth, challenges to lethal injection protocols test the boundaries of the authority and competency of federal courts. Although we must invalidate a lethal injection