"Murder is an offensive act. The term cannot be applied legitimately to any defensive act"

Benjamin Tucker's assertion separates the moral and legal concept of murder from acts of self-defense. To Tucker, murder is inherently offensive, meaning it is initiated without justification against another individual. The essence of calling something murder is deeply tied to the unjustified aggression against another person's rights, most critically their right to life. It is not merely the act of killing but the motivation and context, aggression rather than protection, that defines murder.

By stating that the term cannot be legitimately applied to any defensive act, Tucker draws a crucial distinction. Self-defense arises as a response to an immediate threat; it is reactive, not proactive. Defensive acts, even when they result in the death of an aggressor, are carried out not because of malice or the will to harm, but solely for the preservation of one's own life and safety. To label an act of self-defense as murder would be logically inconsistent and morally unjust, as it ignores the reality of the victim's predicament. Labeling all killing as murder blurs the fundamental difference between malicious harm and justified protection.

Tucker’s ethical framework reflects individualist and libertarian ideals in which the right to one's own life and defense thereof is sacrosanct. Laws and moral judgments, he argues, must be rooted in this acknowledgment of the right to self-preservation. Assigning the language of murder to defensive violence undermines that right, equating victim and aggressor and erasing responsibility for the initial act of force. This perspective ultimately demands clarity in discourse and justice: murder is a crime because it is an unjust infliction of harm, whereas defensive violence resists or seeks to forestall such harm. Only by maintaining this distinction can society rightly adjudicate acts of violence and uphold genuine justice.