PENALTY

neutralized by the evidence of lives saved. The strength of this evidence,
then, carries weight beyond the practical and policy matter
of capital punishment. In this view, the moral legitimacy of the state
depends in part on its willingness to fulfil its obligation to save lives.
Countries like Japan argue that popular support for capital punishment,
including cultural belief in its deterrent value, is reciprocally
tied to the legitimacy of the government itself. 5
But what if the evidence for deterrence is weak, speculative and inconclusive?
Then this logic would be turned on its head. States that execute
in the face of uncertainty about execution’s deterrent effects are implicated
in taking lives without a measurable return beyond vengeance
or retribution. Those states then lose the moral grounding of life-life
trade-offs, and in fact, create risks that reverse the statistical and moral
justification for taking lives. The deaths of people who are innocent, or
lacking in the requisite culpability for execution, become moral casualties
of execution. The costs to state legitimacy are potentially severe,
with the risk of spill-over effects such as deteriorating respect for the
law. 6 Much rides, then, on the evidence for deterrence.
THE EVIDENCE ON THE DEATH PENALTY’S
VALUE AS A DETERRENT
Whether the offense is murder, a drug-related crime or terrorism,
the scientific evidence for deterrence is unreliable, inconclusive and,
in many instances, simply wrong. This has been the conclusion across
a wide range of studies over five decades. While there are no experiments
on execution, nor can there be for obvious moral and ethical
reasons, some studies have examined the effects of moratoria on capital
punishment. Other studies have compared places that practice
capital punishment with carefully matched places that have abolished
or suspended executions and found no differences in murder rates or
other capital-eligible crimes, regardless of the number of executions
in the retentionist places.
5 See for example Mai Sato, The Death Penalty in Japan: Will the Public Tolerate Abolition? (Wiesbaden,
Germany, Springer, 2014); David T. Johnson and Franklin E. Zimring, “Development without
abolition: Japan in the 21st century”, chapter 3 in The Next Frontier: National Development, Political
Change, and the Death Penalty in Asia (New York, Oxford University Press, 2009).
6 Sharon Dolovich, “Legitimate punishment in liberal democracy”, Buffalo Criminal Law Review,
vol. 7 (2004), pp. 307-442
A. Murder
From 1972 to 1976, there was a moratorium on capital punishment
in the United States, inspired in part by growing doubts about its
deterrent effect on murder. 7 Executions resumed following publication
of research claiming that the death penalty did in fact deter
homicides—in fact, that each execution deterred as many as eight
homicides. 8 But that evidence was strongly contested, and a 1978
panel of the National Academy of Sciences found little evidence that
claims of deterrence were accurate. 9 Still, belief in deterrence was
politically and culturally popular, even if scientific evidence didn’t
support it. 10 The belief in deterrence persisted for over two decades,
despite the fact that murder rates rose dramatically in the 1980s just
as executions were increasing.
Two factors undermined those beliefs. First, while the murder rate
began declining sharply in the second half of the 1990s, at the same
time that executions rose sharply, the decline in the murder rate continued
after executions declined sharply in 2000. Second, a large body
of statistical evidence emerged showing that the claims of deterrence
advanced in the early 2000’s were deeply flawed. My own research
showed that the decline in murders starting in 1996 was no greater
in states that continued to sentence and execute murderers than in
states that did not. 11 This included states with a formal moratorium
and states with a de facto moratorium such as California, Illinois and
Pennsylvania, which had large numbers of condemned prisoners but
almost no executions. In those places, despite the absence of executions,
murder rates declined sharply.
7 Furman v. Georgia, 408 U.S. 238, 315 (1972) (Marshall, concurring).
8 Issac Ehrlich, The deterrent effect of capital punishment: A question of life and death”, The American
Economic Review, vol. 65, pp. 397-417 (1975).
9 For a summary, see Brian A. Forst, “Capital punishment and deterrence: Conflicting evidence”,
Journal of Criminal Law and Criminology, vol. 74, pp. 927-942 (1983). See, also, Lawrence R.
Klein, Brian Forst, & Victor Filatov, “The Deterrent Effect of Capital Punishment: An Assessment
of the Estimates”, pp. 336-60 in Alfred Blumstein, Jacqueline Cohen and Daniel Nagin (eds),
Deterrence and Incapacitation: Estimating the Effects of Criminal Sanctions on Crime Rates. Washington,
DC: National Academy of Sciences (1978)
10 Samuel R. Gross, Public opinion on the death penalty: It’s getting personal”, Cornell Law Review,
vol. 83 (1998): pp. 1448-1479
11 Jeffrey Fagan, Franklin E. Zimring, and Amanda Geller. “Capital punishment and capital murder:
Market share and the deterrent effects of the death penalty.” Texas Law Review, vol. 84 pp. 1751 -
2134 (2005).
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