▁and ▁joined ▁by ▁Just ices ▁Anthony ▁Kennedy ▁and ▁Samuel ▁Al ito , ▁held ▁that ▁Kentucky ' s ▁execution ▁method ▁was ▁hum ane ▁and ▁constitution al . ▁In ▁response ▁to ▁the ▁pet ition ers ' ▁argument ▁that ▁the ▁risk ▁of ▁mistakes ▁in ▁the ▁execution ▁protocol ▁was ▁so ▁great ▁as ▁to ▁render ▁it ▁un const itution al , ▁the ▁pl ur ality ▁wrote ▁that ▁" an ▁isolated ▁m ish ap ▁alone ▁does ▁not ▁viol ate ▁the ▁E ighth ▁Am end ment ". ▁It ▁also ▁stated ▁that ▁the ▁first ▁drug ▁in ▁a ▁multi - d rug ▁co ck tail ▁must ▁render ▁the ▁in mate ▁un cons cious . ▁Otherwise , ▁there ▁is ▁a ▁" subst ant ial , ▁constitution ally ▁un accept able ▁risk " ▁that ▁the ▁in mate ▁will ▁suffer ▁a ▁pain ful ▁suff ocation . ▁ ▁Stevens ' ▁conc urrence ▁Justice ▁John ▁Paul ▁Stevens ▁con cur red ▁in ▁the ▁opinion ▁of ▁the ▁Court , ▁writing ▁separately ▁to ▁explain ▁his ▁concerns ▁with ▁the ▁death ▁penalty ▁in ▁general . ▁He ▁wrote ▁that ▁the ▁case ▁question ed ▁the ▁" just ification ▁for ▁the ▁death ▁penalty ▁itself ". ▁He ▁character ized ▁the ▁motiv ation ▁behind ▁the ▁death ▁penalty ▁as ▁an ▁ant ith esis ▁to ▁modern ▁values : ▁ ▁We ▁are ▁left , ▁then , ▁with ▁ret ribution ▁as ▁the ▁primary ▁r ationale ▁for ▁impos ing ▁the ▁death ▁penalty . ▁And ▁indeed , ▁it ▁is ▁the ▁ret ribution ▁r ationale ▁that ▁anim ates ▁much ▁of ▁the ▁remaining ▁enthus ias m ▁for ▁the ▁death ▁penalty . ▁As ▁Lord ▁Justice ▁Den