We reject the dissent's contention that our approach, by largely return[ing] the task of defining the contours of Eighth Amendment protection to political majorities, leaves ‘[c]onstitutional doctrine [to] be formulated by the acts of those institutions which the Constitution is supposed to limit,' [...] By reaching a decision supported neither by constitutional text nor by the demonstrable current standards of our citizens, the dissent displays a failure to appreciate that those institutions which the Constitution is supposed to limit include the Court itself. To say, as the dissent says, that ‘it is for us ultimately to judge whether the Eighth Amendment permits imposition of the death penalty,' (quoting Enmund v. Florida) -- and to mean that as the dissent means it, i.e., that it is for us to judge, not on the basis of what we perceive the Eighth Amendment originally prohibited, or on the basis of what we perceive the society through its democratic processes now overwhelmingly disapproves, but on the basis of what we think proportionate and measurably contributory to acceptable goals of punishment -- to say and mean that, is to replace judges of the law with a committee of philosopher-kings.