(Editor’s note: The information in this special series is for educational purposes only and is not intended to address any particular case, nor should any articles be taken as legal advice.  Always consult with an attorney on any legal matter.)

The goals of the criminal justice system are punishment, rehabilitation and deterrence as well as justice for victims. But, even if the prosecution can prove a defendant is guilty beyond a reasonable doubt, a defendant’s mental state may prevent the case from moving forward.

There are two main areas where a defendant’s mental capacity comes into play – (1) insanity at the time the offense was committed and (2) incompetency at some point in the case, including trial.

The main difference between the two is the time to which they relate. Legal insanity focuses on the time of the commission of the crime. Legal incompetence focuses on the timeframe after the charges are filed and while the case is pending. Legal insanity generally prevents an offender from being held responsible for the crime. It has been explained that a person is legally insane if, at the time of committing the crime, he, as the result of mental disease or defect, was either incapable of knowing what he was doing or that what he was doing was wrong.

On the other hand, a question of an offender’s incompetency asks whether the defendant has sufficient ability to consult with his counsel rationally and has an understanding of the proceedings. A person can be insane at the time he committed the offense but sane afterward. Legal insanity will likely prevent him from being held accountable even if he has regained sanity. On the other hand, someone can be sane when he committed the crime but is deemed incompetent as the case proceeds if the judge finds that he does not have the ability to understand the proceedings or rationally discuss the case with his attorney.

Both insanity and incompetence are required to be proven by a defendant by a preponderance of the evidence. An offender is presumed to be competent until proven otherwise. Insanity and incompetence are occasionally raised by defendants. When raised, the court generally orders the offender to be evaluated by an expert. The majority of time, the expert finds the offender sane and competent.

In a recent newspaper article, there was mention of a local case involving a defendant charged with various acts of harassment and threats toward neighbors. The defendant had been declared incompetent. Because there has been a finding of legal incompetence, the statute requires the proceedings be “stayed” or stalled. The commonwealth cannot list the case for trial while the defendant is incompetent.

When a defendant is deemed incompetent, unless he regains competency, the “stay” cannot last longer than the maximum sentence that is allowable for the crime charged or 10 years, whichever is less. After that time, the charges are dismissed and cannot be pursued. The only exception is for first- and second-degree murder, which shall have no limit on the length of the stay.

Mental capacity can be raised in a variety of ways in a criminal case but claims of insanity and incompetence are the two ways that dictate whether a case can even be pursued despite the existence of evidence to support a finding of guilt beyond a reasonable doubt.