Marshall’s hypothesis has served as the operative premise of the campaign against capital punishment. Abolitionist lawyers, activists, and scholars have taken aim at the assumption of infallibility, compiling an extensive record of mistakes and wrongs in the administration of the death penalty that are pervasive, notwithstanding the Supreme Court’s self-professed best efforts to elaborate a body of law to check them. Yet these efforts to prick the national conscience proceed on an assumption of their own—that the moral reasoner, however approving of the death penalty in theory, indeed should reject it as practiced. But is it so? For all that has been written and said about capital punishment, surprisingly little pursues that critical question.

Lloyd Steffen’s timely book fills the void, providing a valuable guide for all who ask what moral meaning should be made of the death penalty’s fallible practice. Readers will not mistake the author for a death penalty proponent, but they cannot help but appreciate his commitment to engage the penalty’s supporters fairly and on their own terms. Moving methodically from Locke, to Mill, to Kant, Steffen explains how each principal moral perspective advanced in defense of capital punishment gains muscle by bracketing the darker possibilities of the penalty in practice and how each in fact holds out cause for moral doubt (if not outright renunciation) when the brackets are released.

Locke regarded the death penalty as a legitimate option for a civil society interested in self-protection, deterrence, and a means of dispensing justice to an offender—but on an implied condition of fair and unbiased application, enforceable by the natural right of people to dissolve an unjust regime. A long and ongoing history of repressive use of capital punishment worldwide cannot be ignored, however, and Steffen rightly questions whether simple reliance on a political check by the people can satisfy other than the acutely abstracted. Nor can Locke’s position clearly be saved on consequentialist grounds. In perhaps the most compelling portion of the book, Steffen not only lays bare the original weaknesses of Mill’s deterrence-based defense of capital punishment, but demonstrates how hollow the utilitarian’s claim of deterrence rings in a modern American culture that has lost its capacity to be aroused by violence in general and executions in particular. Against the negligible benefits, moreover, must be weighed the costs of wrongful executions—costs hard to accept if one refuses to discount the system’s fallibility or depreciate those who suffer its deadly mistakes as “others” somehow less worthy than one’s self or loved ones. And therein, Steffen proceeds to demonstrate, lies the conundrum that a fallible death penalty practice presents for the retributivist. Kant held the death penalty an unconditionally binding punishment for murder because it affirms the equal moral worth and dignity of all persons. But he too assumed that justice would be fairly administered and that erroneous executions of the innocent would not occur. In our world of inevitable and demonstrable fallibility, are not those who suffer the system’s mistakes denied “the very rights that Kant held to be inviolable” (78)?

Still, the death penalty remains securely lodged in law and culture. Does this persistence suggest that the penalty might find its warrants in a more flexible, “morally moderate” theory of the sort that justifies some but not all wars or, as Steffen argued in an earlier work, some but not all abortions (88)? Steffen exhaustively details the conditions that, if satisfied, could yield the compelling justification required to render the state’s taking of human life “just” by common measures of moral judgment. Yet the theory’s promise, he concludes, cannot be realized in practice. Accurate, fair, nonarbitrary, nondiscriminatory, and even-handed verdicts are essential to a “just execution” practice, and they lie beyond the reach of the judicial system as we know it. Not content to rest with that familiar proposition, however, Steffen cuts to the cultural bone. America’s capital punishment system cannot find its meaning in a theory of just execution because the social demand sustaining it is not, in truth, a demand for justice. Executions symbolize power over the criminal element we fear, and that is their allure.

With that last point, Steffen exposes a possible weakness in Thurgood Marshall’s hypothesis that should disturb opponents and proponents of the death penalty alike. Marshall may have overestimated America’s moral conscience. Morality may have precious little to do with capital punishment’s staying power.