Legal Justifications: Self-Defense and State of Necessity

Characteristics of Unlawful Aggression

Defining Unlawful Aggression

The characteristics of unlawful aggression are fundamental to the doctrine of self-defense. Aggression is defined as an intentional human behavior that:

• Includes both actions and omissions.
• Excludes dangers arising from animals or natural forces.
• Must affect personal legal interests (e.g., person or property).

Aggression must be real. When aggression exists only in the perpetrator's mind, it is termed putative self-defense, which is treated as a case of mistake of law (error of prohibition).

The Requirement of Illegitimacy

The aggression must also be illegitimate. This implies:

• It excludes threats of lawful actions (e.g., exercising a legal right).
• However, it includes defense against an attack from an incompetent person (e.g., a child or mentally ill individual), though such defense should be avoided if possible, as there is no need to invoke the legal system against such an aggressor.

Actual or Imminent Risk

For aggression to fall within the limits of self-defense, it must involve an actual or imminent risk to personal legal interests, whether one's own or those of others.

• There is no legitimate defense against the threat of future harms that can be avoided through regular legal channels.
• Self-defense is not applicable when the attack has ceased and the harm has occurred; that is, when the action is taken to "punish" the offender.

Rational Necessity of Means Employed

Only the action necessary to repel the attack is fully justified, considering the objective circumstances and the subjective perception of the individual, based on an ex ante assessment (before the event).

Proportionality and Justification

The response to aggression is not required to be strictly proportionate. For instance, causing the death of an aggressor may be justified to prevent serious injury to oneself or others, even if, objectively, the harm caused is greater than the harm avoided. However, an excess in the means employed (disproportionate force) typically only allows for the application of an incomplete defense. The individual may also be exempt from punishment through other legal avenues, such as duress.

Lack of Sufficient Provocation

The sufficiency of provocation by the defender must be assessed according to the standard of the average reasonable person and judged ex ante (before the event).

The State of Necessity

Basis for Exemption from Punishment

Similar to self-defense, necessity arises in situations of conflict between two legally protected interests, where one must be sacrificed to save the other. Unlike self-defense, this conflict is not caused by the unlawful aggression of another person. Consequently, neither party whose interests are in conflict is obligated to 'endure' the defensive reaction of the other. Therefore, only conduct that does not cause a greater harm than the one avoided is considered lawful and exempt from punishment.