In recent U.S. Supreme Court litigation involving Eighth Amendment challenges to execution by lethal injection, nitrogen hypoxia and firing squad have been identified as potential alternative methods of execution, including by prisoners themselves, that might—or even must—be used instead of lethal injection, in particular because those methods allegedly carry a lesser risk of pain. The Supreme Court has rejected such arguments in the case of nitrogen hypoxia, in part because it has not been shown that the proffered alternative can be readily implemented by the relevant State and is less likely to cause pain. See Bucklew, 139 S. Ct. at 1129-33 (regarding nitrogen hypoxia); id. at 1142-43 (Breyer, J., dissenting) (same); see also id. at 1136 (Kavanaugh, J., concurring) (regarding firing squad); Glossip, 135 S. Ct. at 2739 (same); id. at 2796-97 (Sotomayor, J., dissenting) (same); Arthur v. Dunn, 137 S. Ct. 725, 733-34 (2017) (Sotomayor, J., dissenting from denial of certiorari) (discussing a prisoner's claim that the firing squad should be imposed as an alternative method in Alabama).