The Role of Mitigating Factors in Capital Sentencing Before and After McKoy v. North Carolina

Abstract

In 1990, the United States Supreme Court ruled that capital jurors do not have to be unanimous in deciding whether or not to accept any particular mitigating circumstance presented to them by the defense during the penalty phase of a capital murder trial. This study examines whether this shift in procedure may have altered the role of mitigation in predicting capital sentencing outcomes by comparing death sentencing predictors before and after the McKoy decision with data from an extensive sample of capital cases in North Carolina tried between 1977 and 2002. The results indicate that (1) both the number of aggravating and mitigating circumstances accepted by capital jurors had statistically significant and substantial effects on capital sentencing outcomes both before and after the McKoy decision; (2) the number of mitigating circumstances presented to and accepted by capital juries in North Carolina doubled during the post‐McKoy period; and (3) the influence of mitigating circumstance on capital sentencing outcomes was attenuated in the post‐McKoy period. Implications of these findings are discussed.