Criminal defendants can only represent themselves if a judge determines that they are competent to do so. The community as a whole has an interest in achieving justice, and a trial in which an incompetent defendant self-represents isn't a fair one.
The case that established that defendants have a right to represent themselves was Faretta v. California, U.S. Sup. Ct. 1975. The Faretta case said that a judge must allow self-representation if a defendant is competent to understand and participate in the court proceedings.
To determine competence, the judge often weighs factors such as:
No single factor determines the result, and a defendant doesn't need the legal skills of a professional lawyer to qualify for self-representation. As long as a defendant is competent, knowingly gives up the right to an attorney, and understands court proceedings, the defendant is entitled to self-represent.
Below are examples of how judges evaluate self-representation requests in criminal cases.
Example: Ella Mental is charged with burglary. Ella has only a grade school education, and she has been in and out of mental institutions for much of her life. Ella tells the judge that she wants to represent herself in the burglary case. The judge allows Ella to do so, on the ground that Ella has been convicted of various crimes three times in the past and is thus familiar enough with criminal law to represent herself. Ella goes to trial, and her questions to prosecution witnesses are garbled and for the most part ruled improper by the judge. Ella is convicted. The judge should not have allowed Ella to represent herself. The mere fact that Ella has three prior convictions does not demonstrate that she is capable of knowingly giving up her right to an attorney and representing herself. In view of her limited education, her history of mental problems, and her inability to participate meaningfully in the trial, the judge should have ignored Ella's wishes and appointed a lawyer to represent her.
Example: Lexi Khan is charged with assault and battery, and she wants to represent herself. Lexi speaks English, but English is her second language and she has trouble understanding some words. She also has trouble reading a law book that the judge asks her to read. In the arraignment court, Lexi refused to enter a plea, and repeatedly said that the whole system is biased and that she wanted nothing to do with it. Over Lexi's objection, the judge appoints an attorney to represent her. Taking all the circumstances into account, the judge properly exercised discretion when denying Lexi's request for self-representation. In view of Lexi's language difficulties and refusal to participate in the arraignment proceedings, Lexi is not capable of representing herself at trial in a meaningful way.
Example: Dane Gerous is charged with aggravated sexual assault and asks to represent himself. The judge's questioning reveals that Dane did not finish high school and has no previous legal experience. However, Dane accurately summarizes the charge that he is facing. Also, when the judge reads a statute to Dane, he is able to explain what it means in his own words. The judge should allow Dane to represent himself. The charge is serious, and the judge may believe that Dane would be better off with a lawyer. However, Dane has demonstrated sufficient ability to understand and participate in the proceedings, and thus, he has a right to represent himself.
It's critical to note, though, that the fact that one can self-represent doesn't mean that one should. Almost everyone who works in the criminal justice system agrees that self-representation is normally a bad idea, in no small part because the defendant usually lacks anything near the necessary training and experience of a criminal defense lawyer.
Whether a defendant is mentally competent to stand trial is a different issue. A time-honored principle in American law holds that we should not subject someone to trial who lacks the capacity to understand the nature and purpose of the legal proceedings against him, to consult with his lawyer, or to help in the preparation of his defense. Someone who is competent to stand trial is oriented as to time and place and has a reasonable degree of rational understanding. (18 U.S.C. § 4241.)
A judge has the power to decide that a defendant is mentally competent to stand trial, yet not competent enough to represent himself. (Indiana v. Edwards, U.S. Sup. Ct. 2008.)