On an initial view, the legal rules relating to the competence of defendants with mental retardation to assist in their own defense' seem both well-settled and well-suited to promote fairness in the criminal process. As the Supreme Court noted in 1975, "it has long been accepted that a person whose mental condition is such that he lacks the capacity to understand the nature and object of the proceedings against him, to consult with counsel, and to assist in preparing his defense may not be subjected to trial."' Whenever a defense attorney has a good faith doubt regarding the competence of his or her client, the attorney is obligated both to seek a clinical evaluation of the issue and to bring his or her doubts to judicial attention. Further, whenever a bonafide doubt arises regarding the defendant's competence, the trial judge is obligated to hold a hearing, whether or not the defense has requested one. This obligation arises at all stages of the proceedings.

A defendant found to be incompetent to stand trial may not be convicted. However, the defendant may be committed for the purpose of assessing the probability that competence can be affected in the foreseeable future and for making efforts to do so.  Although the long-term character of the disability precludes prosecution in many cases, some competence-enhancing interventions may be efficacious. 

Notwithstanding the clarity of these broad legal principles, two problems require attention. First, and most important, there is reason to doubt that, in practice, the interests of defendants with mental retardation are adequately protected. I shall refer to this as the problem of "under-identification." Second, latent ambiguity concerning the concept of incompetence, and the values it is designed to serve, has raised unresolved questions regarding the legal significance of mental retardation in some cases. The problem is most evident in the controversy regarding whether a defendant who is competent to be tried may be found incompetent to plead guilty. Each of these problems is addressed below.

Richard J. Bonnie, The Competence of Criminal Defendants with Mental Retardation to Participate in Their Own Defense, 81 Journal of Criminal Law & Criminology, 419–446 (1990).