Public support for the death penalty increased from the 1970s until the early 1990s, then declined. Our first hypothesis is that the time trend of support can be predicted from press coverage of capital punishment. Our second hypothesis is that the drop since the 1990s has been driven by news media reports of errors in the judicial process, errors that could lead to the executions of innocent people. We tested these two hypotheses by retrieving 39,472 Washington Post and Associated Press stories, then scoring the stories for favorability toward the death penalty - including moral and utilitarian arguments - and statements about the guilt or innocence of the accused. The content analysis scores were entered into the ideodynamic model (Fan 1988) to predict the corresponding time trend in public opinion surveys. The analysis indicated that the change in death penalty support was in fact due to the press turning a spotlight on the condemnation of innocent persons.