University of Cincinnati Law Review


Prosecutors have developed several tactics to effectively lower the burden of proof in criminal trials. One such tactic is to argue to jurors that they should “search for the truth” of what they think happened. Some trial courts are complicit in this effort, and formally instruct jurors “not to search for doubt” but instead “to search for the truth.” Defense lawyers have objected to these truth-based arguments and instructions, as such language improperly lowers the burden of proof below the reasonable doubt standard. Prosecutors, however, have dismissed these objections as pure speculation.

In response to this apparent call for evidence, Dr. Lawrence T. White and I empirically tested the effect of these truth-based jury instructions on verdicts. In two recently published studies, mock jurors who received truth-based instructions convicted at significantly higher rates than those who were simply instructed on reasonable doubt. Jurors who received the truth-based instructions were also far more likely to mistakenly believe it was proper to convict even if they had a reasonable doubt about guilt.

Citing this empirical evidence, defense lawyers have been asking trial courts to remove truth-related language from their burden of proof jury instructions, and to prohibit prosecutors from making search-for-truth arguments to jurors. Prosecutors, however, have responded by attacking the validity of the two published studies.

This Article identifies and debunks these prosecutorial attacks. Its purpose is to assist defense lawyers and judges in recognizing and responding to invalid prosecutorial arguments, many of which are based on a gross misunderstanding of scientific research, blatant misrepresentations of fact or law, and, most significantly, logical fallacies. Debunking these prosecutorial arguments is a critical step in protecting every person’s right to remain free of conviction unless the state can prove guilt beyond a reasonable doubt.