Do I Have the Right to Assistance at Trial by an Expert Witness?

Criminal defendants who cannot afford to pay for an expert witness but need one to mount a defense may wonder if the Constitution grants them the right to expert witness assistance at trial. The Supreme Court has determined – twice – that at a minimum, there is a right to assistance of a mental health expert to evaluate the defendant in death penalty cases. Whether there is a right to expert witness assistance in non-death penalty cases, or whether there is a right to assistance by other types of experts, are open questions.

In Ake v. Oklahoma, 470 U.S. 68 (1985), the Supreme Court determined that the Fourteenth Amendment due process clause requires the government to provide defendants who cannot pay with expert assistance in order to prepare an insanity defense. For the requirement for expert assistance to be triggered, the defendant must make a preliminary showing that his sanity when he allegedly committed the crime will be at issue during trial. In so deciding, the Court evaluated three factors: whether there is a private interest that will be affected by the state’s actions, whether there is value that will be derived from the additional safeguards, and whether providing the assistance will only be a minimal burden to the state.

Only a couple of months ago, the Supreme Court decided a very similar case to Ake, McWilliams v. Dunn, No. 16–5294 (2017). The decision considered whether the expert mental health assistance provided under the Ake decision must be independent of the prosecution; in other words, whether using a single mental evaluation available to both parties was sufficient under Ake. The Court, in a 5-4 decision, said it was not sufficient. Importantly, the Court did not decide whether the government must provide the defense with its own expert retained specifically for only the defense.

In any case, these decisions apply very narrowly to death penalty (capital) cases and to mental health experts. The Supreme Court has not decided whether any other type of expert is required or whether expert assistance is required in any other type of case (such as a DUI case, where expert testimony about breathalyzer or blood test results can be key). The Court has declined to state whether the government must provide the defense with a different expert than that used by the prosecution. All these questions could be very important for DUI defendants, who often cannot afford to retain expensive experts.

To learn more about expert testimony during jury trials for people charged with DUIs, seek out the local DUI attorney who cares about seeking the best outcomes for his clients. Clint Patterson, Esq., of Patterson Law Firm, a former Tulsa prosecutor, is familiar with the pros and cons of jury versus bench trials. Schedule a case evaluation by visiting Patterson Law Firm online or calling Clint’s office at (918) 550-9175.