Cass R. Sunstein and Adrian Vermeule, "Is Capital Punishment Morally Required? The Relevance of Life-Life Tradeoffs," AEI-Brookings Joint Center for Regulatory Studies, March 2005, pp. 1-3, 7-11, 41-42. http://aei-brookings.org. © 2005 by Cass R. Sunstein and Adrian Vermeule. All rights reserved. Reproduced by permission.
Cass R. Sunstein is a professor of jurisprudence at the University of Chicago Law School, and Adrian Vermeule is a professor of law at the University of Chicago.
Many people believe capital punishment is morally impermissible. In their view, executions are inherently cruel and barbaric. Often they add that capital punishment is not, and cannot be, imposed in a way that adheres to the rule of law. They contend that as administered, capital punishment ensures the execution of (some) innocent people, and also that it reflects arbitrariness, in the form of random or invidious infliction of the ultimate penalty.
Defenders of capital punishment come in two different camps. Some are retributivists. Following [the philospher Immanuel] Kant, they claim that for the most heinous forms of wrongdoing, the penalty of death is morally justified or perhaps even required. Other defenders of capital punishment are consequentialists and often also welfarists. They contend that the deterrent effect of capital punishment is significant and that it justifies the infliction of the ultimate penalty. Consequentialist defenses of capital punishment, however, tend to assume that capital punishment is (merely) morally permissible, as opposed to being morally obligatory.
State Omissions Are Morally Important
Our goal here is to suggest that the debate over capital punishment is rooted in an unquestioned assumption, and that the failure to question that assumption is a serious moral error. The assumption is that for governments, acts are morally different from omissions. We want to raise the possibility that an indefensible form of the act-omission distinction is crucial to the most prominent objections to capital punishment—and that defenders of capital punishment, apparently making the same distinction, have failed to notice that on the logic of their theory, capital punishment is morally obligatory, not just permissible. We want to suggest, in other words, that capital punishment may be morally required not for retributive reasons, but in order to prevent the taking of innocent lives.
The foundation for our argument is a large and growing body of evidence that capital punishment may well have a deterrent effect, possibly a quite powerful one.
The suggestion bears not only on moral and political debates, but also on constitutional questions. In invalidating the death penalty for juveniles, for example, the Supreme Court did not seriously engage the possibility that capital punishment for juveniles may help to prevent the death of innocents, including the deaths of juvenile innocents. And if our suggestion is correct, it is connected to many questions outside of the context of capital punishment. If omissions by the state are often indistinguishable, in principle, from actions by the state, then a wide range of apparent failures to act—in the context not only of criminal and civil law, but of regulatory law as well—should be taken to raise serious moral and legal problems. Those who accept our arguments in favor of the death penalty may or may not welcome the implications for government action in general. In many situations, ranging from environmental quality to highway safety to relief of poverty, our arguments suggest that in light of imaginable empirical findings, government is obliged to provide far more protection than it now does, and that it should not be permitted to hide behind unhelpful distinctions between acts and omissions.
Growing Evidence that Capital Punishment Is a Deterrent
The foundation for our argument is a large and growing body of evidence that capital punishment may well have a deterrent effect, possibly a quite powerful one. A leading study suggests that each execution prevents some eighteen murders, on average. The particular numbers do not much matter. If the current evidence is even roughly correct, then a refusal to impose capital punishment will effectively condemn numerous innocent people to death. States that choose life imprisonment, when they might choose capital punishment, are ensuring the deaths of a large number of innocent people. On moral grounds, a choice that effectively condemns large numbers of people to death seems objectionable to say the least. For those who are inclined to be skeptical of capital punishment for moral reasons—a group that includes one of the current authors—the task is to consider the possibility that the failure to impose capital punishment is, prima facie and all things considered, a serious moral wrong....
For many years, the deterrent effect of capital punishment was sharply disputed. But a great deal of recent evidence strengthens the claim that capital punishment has large deterrent effects. The reason for the shift is that a wave of sophisticated econometric studies have exploited a newly-available form of data, so-called "panel data" that uses all information from a set of units (states or counties) and follows that data over an extended period of time. A leading study used county-level panel data from 3,054 U.S. counties between 1977 and 1996. The authors find that the murder rate is significantly reduced by both death sentences and executions. The most striking finding is that on average, each execution results in 18 fewer murders.
Other econometric studies also find a substantial deterrent effect. In two papers, Paul Zimmerman [a senior economist with the Federal Communications Commission] uses state-level panel data from 1978 onwards to measure the deterrent effect of execution rates and execution methods. He estimates that each execution deters an average of fourteen murders. Using state-level data from 1977 to 1997, [H. Naci] Mocan and [R. Kaj] Gittings [economics professors at the University of Colorado at Denver] find that each execution deters five murders on average. They also find that increases in the murder rate come from removing people from death row and also from commutations in death sentences. Yet another study, based on state-level data from 1997-1999, finds that a death sentence deters 4.5 murders and an execution deters three murders. The same study investigates the question whether executions deter crimes of passion and murders by intimates. The answer is clear: these categories of murder are deterred by capital punishment. The deterrent effect of the death penalty is also found to be a function of the length of waits on death row, with a murder deterred for every 2.75 years of reduction in the period before execution.
In the period between 1972 and 1976, the Supreme Court produced an effective moratorium on capital punishment, and an extensive study exploits that fact to estimate the deterrent effect. Using state-level data from 1960-2000, the authors make before-and-after comparisons, focusing on the murder rate in each state before and after the death penalty was suspended and reinstated. The authors find a substantial deterrent effect. After suspending the death penalty, 91% of states faced an increase in homicides—and in 67% of states, the rate was decreased after reinstatement of capital punishment.
It hardly seems sensible that governments should ignore evidence demonstrating a significant possibility that a certain step will save large numbers of innocent lives.
A recent study offers more refined findings. Disaggregating the data on a state by state basis, [economist] Joanna Shepherd finds that the nation-wide deterrent effect of capital punishment is entirely driven by only six states—and that no deterrent effect can be found in the twenty-one other states that have restored capital punishment. What distinguishes the six from the twenty-one? The answer lies in the fact that states showing a deterrent effect are executing more people than states that do not. In fact the data show a "threshold effect": deterrence is found in states that had at least nine executions between 1977 and 1996. In states below that threshold, no deterrence can be found. This finding is intuitively plausible. Unless executions reach a certain level, murderers may act as if the death is so improbable as not to be worthy of concern. Her main lesson is that once the level of executions reaches a certain level, the deterrent effect of capital punishment is substantial.
Governments Should Not Ignore Evidence
All in all, the recent evidence of a deterrent effect from capital punishment seems impressive. But in studies of this kind, it is hard to control for confounding variables, and a degree of doubt inevitably remains. It remains possible that these findings will be exposed as statistical artifacts or will be found to rest on flawed econometric methods. More broadly, skeptics are likely to question the mechanisms by which capital punishment has a deterrent effect. On the skeptical view, many murderers lack a clear sense of the likelihood and perhaps even the existence of executions in their state; further problems for the deterrence claim are introduced by the fact that capital punishment is imposed infrequently and after long delays. In any case many murders are committed in a passionate state that does not lend itself to an all-things-considered analysis on the part of perpetrators....
These suppositions are in some tension with existing evidence. But let us suppose that these doubts are reasonable. If so, should current findings be deemed irrelevant for purposes of policy and law? That would be an odd conclusion. In regulation as a whole, it is common to embrace some version of the Precautionary Principle—the idea that steps should be taken to prevent significant harm even if cause-and-effect relationships remain unclear and even if the risk is not likely to come to fruition. Even if we reject strong versions of the Precautionary Principle, it hardly seems sensible that governments should ignore evidence demonstrating a significant possibility that a certain step will save large numbers of innocent lives.
For capital punishment, critics often seem to assume that evidence on deterrent effects should be ignored if reasonable questions can be raised about it. But as a general rule, this is implausible. In most contexts, the existence of reasonable questions is hardly an adequate reason to ignore evidence of severe harm. If it were, many environmental controls would be in serious jeopardy. We do not mean to suggest that government should commit what many people consider to be, prima facie, a serious moral wrong simply on the basis of speculation that this step will do some good. But a degree of reasonable doubt does not seem sufficient to doom capital punishment, if the evidence suggests that significant deterrence occurs.
If capital punishment does have a strong deterrent effect, there is a crucial implication: it must be the case that capital punishment is not a wholly capricious system of punishment, pervaded by false positives.
In any event, we will proceed by stipulating to the validity of this evidence, in order to isolate the question of its moral significance. Our primary concern here is not to reach a final judgment about the evidence, but how to evaluate capital punishment given the assumption of a substantial deterrent effect. Those who doubt the evidence might ask themselves how they would assess the moral questions if they were ultimately convinced that life-life tradeoffs were actually involved—as, for example, in hostage situations in which officials are authorized to use deadly force to protect the lives of innocent people.
Capital Punishment Has a High Degree of Accuracy
If capital punishment does have a strong deterrent effect, there is a crucial implication: it must be the case that capital punishment is not a wholly capricious system of punishment, pervaded by false positives. At the very least, some or many prospective murderers must believe that the system has a high degree of accuracy. The simple reason is that if capital punishment were thoroughly error-prone and seen as such, the deterrent signal of the punishment would be so diluted that it would be extremely unlikely to produce such strong and consistent empirical traces as those described above. At the limit, if capital punishment were entirely random, falling with utter arbitrariness upon innocent and guilty alike, there would be no reason for any prospective criminal to factor it into calculations about the costs and benefits of crime.... Of course it remains undeniable that capital punishment is sometimes imposed erroneously, and undeniable too that it is sometimes imposed arbitrarily or on invidious grounds within the set of guilty defendants. Nothing we say here is meant to suggest that states should be content with erroneous or arbitrary death sentences. But the evidence suggests that there is at least a high degree of accuracy, in the sense of avoiding false positives, in the infliction of capital punishment....
Governments Without Capital Punishment May Be Violating Citizen Rights
We conjecture that something like the following set of views about capital punishment has been and probably still is widespread in the legal academy. Capital punishment does not deter, or at least the evidence that it does so is essentially nonexistent; some categories of murders, especially crimes of passion, are undeterrable (at least by capital punishment); even if capital punishment has a deterrent effect, the effect is marginal, perhaps because of the relatively small number of capital sentences and the long time lags between sentencing and execution; the system of capital punishment is rife with error and arbitrariness.
A government that settles upon a package of crime-control policies that does not include capital punishment might well seem ... to be both violating the rights and reducing the welfare of its citizens.
The recent evidence raises doubts about all of these views. Capital punishment may well have strong deterrent effects; there is evidence that few categories of murders are inherently undeterrable, even so-called crimes of passion; some studies find extremely large deterrent effects; error and arbitrariness undoubtedly occur, but the evidence of deterrence suggests that prospective murderers are receiving a clear signal.
The moral and legal commentary on capital punishment ought to be sensitive to any significant revision in what we know. Life-life tradeoffs are inescapably involved. In light of recent evidence, a government that settles upon a package of crime-control policies that does not include capital punishment might well seem, at least prima facie, to be both violating the rights and reducing the welfare of its citizens—just as would a state that failed to enact simple environmental measures promising to save a great many lives.
Capital Punishment May Be Morally Obligatory
The most common basis for resisting this conclusion, and our principal target here, is some version of the distinction between acts and omissions. Opponents of capital punishment frequently appeal to an intuition that intentional killing by the government and its agents is morally objectionable in a way that simply allowing private killings is not. Whatever the general merits of the distinction between acts and omissions in the moral theory of individual conduct, we think it gets little purchase on questions of governmental policy. Government cannot help but act in ways that affect the actions of citizens; where citizens decide whether or not to kill each other in light of government's policies, it is not clear even as a conceptual matter what it would mean for government not to act. For government to adopt a mix of criminal-justice policies that happens not to include capital punishment is not an "omission" or a "failure to act" in any meaningful sense. Likewise, deontological injunctions against unjustified killing, which we have not questioned here, are of little help in these settings. Unjustified killing is exactly what capital punishment prevents.
If the recent evidence of deterrence is shown to be correct, then opponents of capital punishment will face an uphill struggle on moral grounds.
If this argument is correct, it has broad implications, some of which may not be welcomed by advocates of capital punishment. Government engages in countless omissions, many of which threaten people's health and safety; consider the failure to reduce highway fatalities, to regulate greenhouse gas emissions, to prevent domestic violence, to impose further controls on private uses of guns, even to redistribute wealth to those who most need it. Suppose that it is not sensible, in these and other contexts, to characterize government omissions as such, or suppose that even if the characterization is sensible, it lacks moral relevance. If so, then government might well be compelled, on one or another ground, to take steps to protect people against statistical risks, even if those steps impose costs and harms; much will depend on what the facts show.
Any objection to capital punishment, we believe, must rely on something other than abstract injunctions against the taking of life. If the recent evidence of deterrence is shown to be correct, then opponents of capital punishment will face an uphill struggle on moral grounds. If each execution is saving many lives, the harms of capital punishment would have to be very great to justify its abolition, far greater than most critics have heretofore alleged. There is always residual uncertainty in social science and legal policy, and we have attempted to describe, rather than to defend, recent findings here. But if those findings are ultimately shown to be right, capital punishment has a strong claim to being, not merely morally permissible, but morally obligatory, above all from the standpoint of those who wish to protect life.