States have their own penal codes, but in general follow common doctrine as it is embodied in federal law. In criminal defense, there are doctrines that are acceptable in most courts that will mitigate or nullify a criminal charge. Below is a list of the most common criminal defense doctrines.
The defendant justifies a criminal act because it was to and did prevent a greater evil and there was no other legal alternative. An example would be a person charged with driving under the influence (DUI) may argue that driving prevented a kidnapping. This is a complex issue, and courts are careful about accepting this type of defense.
This is usually a partial affirmative defense in which the defendant maintains that the act was committed in an unavoidable situation and under the immediate threat of death, violence or harm by a third party of the defendant or another person. An example would be robbing a bank under the direction of another person who will otherwise kill a family member who is under that other person’s control.
This is a defense that includes involuntary intoxication and diminished capacity, in which the defendant maintains he or she had no control over their activities, or did not know right from wrong because of some permanent impairment or because of a temporary incapacity from the effects of a drug or other chemical. An example would be a drunk driving charge in which the defendant had unknowingly ingested alcohol at a party i.e. spiked punch.
This is a familiar defense against charges of murder or battery, in which the defendant maintains the criminal act was executed as protection from the victim’s own violence. With this defense, the defendant has to prove that the use of force was reasonable, and that the situation could not be avoided. An example would be a woman being raped hitting the person on the head with a rock to get away from her attacker.
It is possible to avoid a conviction by claiming a mistake of fact. This is different from ignorance of the law which is not admissible as a defense. A person may known the law but still break it because of a misrepresentation or misunderstanding of the facts. An example would be the defendant entered a stranger’s house by mistake. While it is technically trespassing, there was no intention to do so.
These are by no means a complete list of criminal defense doctrines, but they are some of the most popular. If you ever need to choose one as a practical matter, leave it to your criminal defense lawyer to decide which one.read more