When the defendant’s acts are the product of natural causes, the criminal law enables necessity to be used as a defence in court.
When the defendant’s acts are the product of natural causes, the criminal law enables necessity to be used as a defence in court. This argument is distinct from the duress defence, which may be used when the defendant’s conduct were the product of coercive human control. Self-defense is often considered a kind of necessity, since it is the natural impulse to protect oneself from danger that causes the violence, rather than the force of another human being. (In fact, it’s hardly a stretch to consider “self defence” a subclass of necessity defence.) Another possible use of the necessity argument would be for a defendant convicted of speeding if he was driving to the emergency room while carrying a heart attack sufferer in the rear seat.
Certain actions of necessity may sometimes be used as a defence if they are expressly included in the legislation outlining the offence. A notable example of this, while it is no longer applicable after the Roe v. Wade verdict, was the abortion statute, which included a clause that authorised conducting an abortion in order to save the mother’s life.
However, the breadth of necessity as a defence is quite restricted. Most courts demand an exceptionally strong necessity to justify breaching the law, and some courts have even abolished the defence entirely. In general, the necessity defence requires that the defendant’s damage be smaller than the harm averted. To use an example from self-defense, a man’s threat of violence may nearly never justify that man’s murder.