This well-known maxim reflects the theoretical basis of the defence of necessity: that in dire circumstances of looming peril, the claims of positive law seems to weaken.
232[1] in which Dickson J. described the rationale for the defence as a recognition that: a liberal and humane criminal law cannot hold people to the strict obedience of laws in emergency situations where normal human instincts, whether of self-preservation or of altruism, overwhelmingly impel disobedience.
At a minimum the situation must be so emergent and the peril must be so pressing that normal human instincts cry out for action and make a counsel of patience unreasonable.With regard to the second element, if there was a reasonable legal alternative to breaking the law, then there can be no finding of necessity.
The first two elements must be proven according to the modified objective standard, which takes into account the situation and characteristics of the particular accused person (see R. v. Latimer (2001) at §§ 32–34).
When evaluating the gravity of the act, a matter of community standards infused with constitutional considerations of the accused and the victim are considered.
Perka v The Queen (1984) provides a summary on the nature, basis and limitations on the defence of necessity: (1) the defence of necessity could be conceptualized as either a justification or an excuse; (2) it should be recognized in Canada as an excuse, operating by virtue of s. 7(3) of the Criminal Code; (3) necessity as an excuse implies no vindication of the deeds of the actor; (4) the criterion is the moral involuntariness of the wrongful action; (5) this involvement is measured on the basis of society's expectation of appropriate and normal resistance to pressure; (6) negligence or involvement in criminal or immoral activity does not disentitle the actor to the excuse of necessity; (7) actions or circumstances which indicate that the wrongful deed was not truly involuntary do disentitle; (8) the existence of a reasonable legal alternative similarly disentitles; to be involuntary the act must be inevitable, unavoidable and afford no reasonable opportunity for an alternative course of action that does not involve a breach of the law; (9) the defence only applies in circumstances of imminent risk where the action was taken to avoid a direct and immediate peril; (10) where the accused places before the court sufficient evidence to raise the issue, the onus is on the Crown to meet it beyond a reasonable doubt.
The Supreme Court of Canada restore the acquittal from trial on the basis that the accused "had a reasonable belief that the circumstances afforded him no legal way out" and the lethal attack he sought to avoid outweighed his breach of s. 88(1) (at para 96).
In these circumstances, reasonable person could withstand the pressure to defy the court order and thus, the accused's honest belief that abortion was immoral does not change this fact.
The defendant drove to a hill, parking in the centre of the road and hoping he would be found by a passerby, but was discovered by officers.
The threat the defendant posed by parking in the centre of a road at night unaware and without lights was found to outweigh the harm avoided.
In Perka v. The Queen, the Court explores the history of the necessity defence in order to determine whether it is an excuse or a justification.