The non-aggression principle has been considered the pillar of the philosophical underpinnings of libertarianism. In a nutshell, the non-aggression principle forbids us from imposing undue harm upon another. Whether it be through violent action or misappropriation of their property. However, under these philosophical precepts, violent action is only justified if it is for self-defense. The non-aggression principle does not mention anything overtly about voluntary violence. If two adults of sound mind get into a fistfight, clearly articulate the terms of the skirmish, and do not withdraw consent at any point how could this be illegitimate? Both parties agree to these terms and neither choose to abruptly end the confrontation. If we rigidly apply the NAP would a consensual fight violate its terms? In a narrow sense, we already have voluntary violence in American society. Anyone who willingly participates in combat sports such as mixed-martial arts engages in consensual acts of violence. To a lesser and more oblique manner, anyone who has participated in sadomasochistic sexual acts has also consented to engage in violent acts. If consent is the operative contingency that separates charity from theft and intercourse from rape, then why couldn’t it be applied in more novel applications?
For example, why does law enforcement need to be immediately notified of a brawl in the parking lot of a bar? Often, bystanders not affiliated with the bar nor patron will automatically resort to calling the police. Even though they are merely witnessing the fight from across the street. If the bar owner and the two patrons fighting are all okay with the arrangement, then it would be transgressive to call the police. While a bare-knuckles brawl in a bar parking lot is tantamount to how Neanderthal would solve a dispute, if it isn’t harming anyone else then it isn’t a problem. Unless a bystander happens to get hit by accident. Then the prospect of ligation rears its ugly head. Although both quarreling patrons may consent to the fight, they may still sue the bar owner in the event of sustaining serious injuries. This can be remedied by having the customers wishing to fight on the premise to sign a waiver absolving the bar owner of any responsibility for personal injuries sustained. This perspective may be unorthodox as conventional wisdom suggests we should alert the authorities regardless of whether the two men consent to the conditions of the fight or not.
Another form of voluntary violence that has become viewed as a barbaric anachronism is the old institution of “trial by combat”. This may seem antithetical to our modern convention of evidence-based innocence. In the honor-based culture of medieval Europe, such as test was viewed as being completely valid. Why not? We sentence murders to death in our current legal system, so what if we were to have an accused murder fight for their life? The suspect, the court, and the family of the victim would all have to agree to this arrangement. They would also have to be unanimous agreement also in the parameters of the trial. The weapons that could be used, what are the rules of engagement, the conditions under which the suspect would be exonerated in the event of a victory. If the suspect is guilty and an inept fighter then it is analogous to being executed. But if the suspect is innocent but is killed in the trial, then it would be something of an injustice. However, it would be an injustice he fully consented to. The private law court in which he provided this option as a form of the trial made him sign a document. This document detailed all the potential hazards of this form of legal trial and required him to acknowledge the risks. Once he signed on the dotted line he transferred his right to an evidence-based trial (the common form of trials in liberal democracies) away to the court.
The other old-fashioned form of voluntary violence is the practice of dueling. Considering we as a society have “evolved” beyond handling disputes in such a manner (why would you when you can launch a tactical drone strike) this method of conflict resolution seems primitive. Again, if the participants provide mutual consent and do not at any point withdraw that consent. Part of that consent requires agreement on the parameters of this engagement. What kind of weapons should be used, how many paces before commencing the attack, will the victor be responsible for the medical bills of the loser (providing he survives), is this a fight to the death or merely the first contact? All of this rule formulation is a crucial component of establishing consent. Violating any of these informal rules would be equal to transgressing against the other party involved in the duel. Making the rules transparent and to adhere to them is paramount in establishing the legitimacy of the duel. Another part of keeping this arrangement legitimate would be to manage it in such a manner that would limit spillover effects. A prime example of this would be a spectator or bystander getting hit by a stray bullet. If this were to happen the duelers would be held liable for damages. Such externalities could be limited by the choice of weaponry or even tapping off a safe perimeter in the surrounding areas where the duel is planned to take place. Another alternative would be to allow spectators to observe the duel near the action. The audience members would in turn relinquish their right to not be subjected to violence. Essentially selling this right for up-close and personal entertainment. They relinquish this right by signing a waiver saying they acknowledge the risks and will not sue for damage if on the off-chance they are injured.