Opinion of the Court
offenders. The theory of deterrence in capital sentencing is predicated upon the notion that the increased severity of the punishment will inhibit criminal actors from carrying out murderous conduct. Yet it is the same cognitive and behavioral impairments that make these defendants less morally culpable—for example, the diminished ability to understand and process information, to learn from experience, to engage in logical reasoning, or to control impulses—that also make it less likely that they can process the information of the possibility of execution as a penalty and, as a result, control their conduct based upon that information. Nor will exempting the mentally retarded from execution lessen the deterrent effect of the death penalty with respect to offenders who are not mentally retarded. Such individuals are unprotected by the exemption and will continue to face the threat of execution. Thus, executing the mentally retarded will not measurably further the goal of deterrence.
The reduced capacity of mentally retarded offenders provides a second justification for a categorical rule making such offenders ineligible for the death penalty. The risk "that the death penalty will be imposed in spite of factors which may call for a less severe penalty," Lockett v. Ohio, 438 U. S. 586, 605 (1978), is enhanced, not only by the possibility of false confessions,25 but also by the lesser ability of mentally retarded defendants to make a persuasive showing of mitigation in the face of prosecutorial evidence of one or more aggravating factors. Mentally retarded defendants may be less able to give meaningful assistance to their counsel and
25 See Everington & Fulero 212-213. Despite the heavy burden that the prosecution must shoulder in capital cases, we cannot ignore the fact that in recent years a disturbing number of inmates on death row have been exonerated. These exonerations have included at least one mentally retarded person who unwittingly confessed to a crime that he did not commit. See Baker, Death-Row Inmate Gets Clemency; Agreement Ends Day of Suspense, Washington Post, Jan. 15, 1994, p. A1.Page: Index Previous 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Next
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