A study entitled "State Public Opinion, the Death Penalty, and the Practice of Electing Judges" and published in the April 2008 American Journal of Political Science found significant links between public opinion and judicial decision-making in states that elect their supreme court judges.
Newly available measurement techniques and data on public opinion permitted political scientists to examine connections between public opinion about capital punishment and judicial decisions in capital cases in states where members of the state supreme court are elected rather than appointed.
Previous studies have shown that sentencing generally becomes more punitive in elective states as elections near, even where they are nonpartisan retention elections that receive little attention from the public. Noting that a new style of judicial campaigning recently has emerged, in which candidates engage in heated races and seek to capture more attention by focusing on the public's general fear of crime and support for capital punishment, the authors hypothesized that judges' decisions in death penalty cases would be affected by public opinion in elective, but not in non-elective, states.
Controlling for factors including quality of representation and complexity of the case on appeal, the study found that, in states that elect judges, higher levels of public support for capital punishment are associated with significantly lower probabilities of voting to reverse death sentences. Where campaign restrictions prevent judicial candidates from taking a position on capital punishment, the data reveals a significant increase in the probability of reversal votes.
The study also found that, in elective states where supreme court judges rule on death penalty cases, stronger public support for the death penalty produces significantly more conservative judges than predicted based on state ideology alone, and those judges are more likely to uphold death sentences.
The study concluded that elections and strong public opinion exert a notable and significant direct influence on decision-making in death penalty cases.