Capital Punishment Does Not Deter Homicides

Perhaps the most important articulation of the U.S. Supreme Court’s conception of its death penalty jurisprudence appeared in the 2002 opinion in Atkins v. Virginia:

Gregg v. Georgia, 428 U. S. 153, 183 (1976) (joint opinion of Stewart, Powell, and Stevens, JJ.), identified “retribution and deterrence of capital crimes by prospective offenders” as the social purposes served by the death penalty. Unless the imposition of the death penalty … “measurably contributes to one or both of these goals, it ‘is nothing more than the purposeless and needless imposition of pain and suffering,’ and hence an unconstitutional punishment.” Enmund, 458 U. S., at 798.

The Court’s statement evokes the great Italian criminologist Cesare Beccaria’s 1764 treatise, On Crimes and Punishments, which had a profound influence on the American Founding Fathers, in part due to its famous chapter on the death penalty. In Of the Punishment of Death, Beccaria articulated the view the U.S. Supreme Court has now adopted, stating that a punishment only promotes justice insofar as it is proportionate and “ha[s] only that degree of severity which is sufficient to deter others.”

Beccaria went on to state that, since life imprisonment “has in it all that is necessary to deter the most hardened and determined,” the death penalty could not be a just expression of state power since the death penalty is not a more effective deterrent than life imprisonment. Id. at 101-02. Beccaria noted that capital punishment may independently decrease deterrence by making citizens callous to the taking of another’s life with “the example of barbarity it affords.” Id. at 104. Amazingly, Beccaria intuited (at age 26!) what the best empirical research of the last thirty years has shown to be true in America: the death penalty is not a deterrent to homicide. Let’s consider the relevant factors and the evidence.

Some believe that they can resolve the question of whether the death penalty deters by a simple syllogistic argument that refutes Beccaria’s conclusion: capital punishment is worse than other penalties therefore it must lead to fewer killings. This contention misses much of the complexity of the modern death penalty. First, this argument ignores Beccaria’s admonition that the spectacle of state-sanctioned killings operates to unhinge marginal minds into thinking that their own grievances merit similar forms of retribution that they will then be inclined to inflict through their own homicidal behavior. Even if some criminals were deterred by the death penalty, one must ask whether these avoided crimes would be offset by the brutalization effect that Beccaria emphasized.

Second, operating a death penalty regime – at least in the United States – has been incredibly costly, as each case resulting in a death sentence will spend years in various types of legal appeals, eating up the valuable time of judges, prosecutors, and defense lawyers, overwhelmingly at government expense. Nowhere has this been more evident than in the capital punishment regime of the State of California.

The best research on the issue suggests that life imprisonment is a less costly penalty, since locking someone up is far less expensive than both locking them up and paying a team of lawyers for many years – often decades – to debate whether a sentence of death should be imposed. In California, for example, execution is only the third leading cause of death for those on death row (behind old age and suicide).

Some might contend that the lengthy appeals are a needless burden that should be jettisoned so that the penalty is administered more cheaply and quickly, but the large number of exonerations of those on death row (155 including 21 by DNA evidence at last count) underscores the danger of any effort to short circuit the judicial process. Killing a few innocent defendants is an unavoidable consequence of having a capital regime – so unless there is some clear evidence of deterrence, it is hard to argue positively for the death penalty.

So what is the evidence on deterrence? Here the answer is clear: there is not the slightest credible statistical evidence that capital punishment reduces the rate of homicide. Whether one compares the similar movements of homicide in Canada and the US when only the latter restored the death penalty, or in American states that have abolished it versus those that retain it, or in Hong Kong and Singapore (the first abolishing the death penalty in the mid-1990s and the second greatly increasing its usage at the same), there is no detectable effect of capital punishment on crime. The best econometric studies reach the same conclusion.

A number of studies purported to find deterrent effects but all of these studies collapse after errors in coding, measuring statistical significance, or in establishing causal relationships are corrected, as shown in twostudies. A panel of the National Academy of Sciences addressed the deterrence question directly in 2012 and unanimously concluded that there was no credible evidence that the death penalty deters homicides. This opinion was joined by the conservative scholar James Q. Wilson, who had previously written in support of capital punishment.

The unanimous report went on to say that the issue of deterrence should be removed from any discussion of the death penalty given this lack of credible evidence. But if the deterrence argument disappears, so does the case for the death penalty.

Those familiar with criminal justice issues are not surprised by the lack of deterrence. To get the death penalty in the United States one has to commit an extraordinarily heinous crime, as evidenced by the fact that last year roughly 14,000 murders were committed but only 35 executions took place.

Since murderers typically expose themselves to far greater immediate risks, the likelihood is incredibly remote that some small chance of execution many years after committing a crime will influence the behavior of a sociopathic deviant who would otherwise be willing to kill if his only penalty were life imprisonment.

Any criminal who actually thought he would be caught would find the prospect of life without parole to be a monumental penalty. Any criminal who didn’t think he would be caught would be untroubled by any sanction.

A better way to address the problem of homicide is to take the resources that would otherwise be wasted in operating a death penalty regime and use them on strategies that are known to reduce crime, such as hiring and properly training police officers and solving crimes.

Over the past three decades there has been a downward trend in the number of murders that lead to arrest and conviction to the point that only about half of all murders are now punished. The graphic below shows the steady decline in the number of homicides cleared by arrest in Connecticut, which mimics the national trend. Of course, even if there is an arrest, there may not be a conviction so the percentage of killers who are punished is smaller than this figure suggests.

Connecticut murder cases cleared by arrest or other means: 1970 - 2009

Far better for both justice and deterrence if the resources saved by scrapping the death penalty could be used to increase the chance that killers would be caught and punished – and taken off the streets.

To give a sense of the burden of capital punishment, note that over the past 35 years the state of California spent roughly $4 billion to execute 13 individuals. The $4 billion would have been enough to hire roughly 80,000 police officers who, if appropriately assigned, would be expected to prevent almost 500 murders (and much other crime) in California – far more than any of the most optimistic (albeit discredited) views of the possible benefits of capital punishment.

In other words, since the death penalty is a costly and inefficient system, its use will waste resources that could be expended on crime-fighting measures that are known to be effective. It is not surprising that last summer the trial judge in Jones v. Davis ruled that California’s capital regime is unconstitutional on the grounds that it serves no legitimate penological interest.

The sharp decline in executions in the US from the peak of 98 in 1999 down to 35 last year (with death sentences falling from a 1996 peak of 315 to 73), coupled with the steady pace of states abolishing the death penalty over the past eight years (including conservative Nebraska in May and Connecticut entirely in August) shows that “smart on crime” entails shunning capital punishment.

With zero evidence that the death penalty provides any tangible benefits and very clear indications of its monetary, human, and social costs, a strong case exists for the view that capital punishment in the United States in general, and in California in particular, “‘is nothing more than the purposeless and needless imposition of pain and suffering,’ and hence an unconstitutional punishment.”

The amicus brief filed by the Empirical Scholars in Jones v. Davis is below: