Libertarians apply the non-aggression principle to both interpersonal and geopolitical conflicts. This means that self-defense is justified against a threat of any size, whether it be from an individual or an entire army. Put simply, we are morally justified in employing violence only to deter an attack.

Of course, not all wars involved groups of people with similar size, skill, and supplies. Those being attacked are, in many cases, ill-equipped and largely defenseless, leading to outright slaughter, and in some scenarios, borderline genocide. Many libertarians struggle to reconcile their political philosophy with this very real circumstance. It’s a question we must all ponder: is war justified when it’s being done in defense of a defenseless, victimized third party?

A strict interpretation of just war theory and the non-aggression principle would lead most people to conclude that the answer is no. My answer is a qualified yes.

I have the right to defend myself from an attack. Because I have that right, and a corresponding moral authority and responsibility, I can therefore partially delegate the responsibility to another individual. This delegation allows me to employ a bodyguard or other security officer to help defend me—it’s simply an extension of my own innate and individual authority.

This is an explicit delegation of authority, since I have actively consented to the agreement, whether verbally or in writing. The answer to our original question of defending the defenseless lies in understanding how an implicit delegation of authority might work.

Let’s start with a very basic example. You’re walking along the street and you see a woman being sexually abused. She’s being restrained and gagged, unable to cry out for help, but it’s extremely obvious that she is not consenting to what is occurring. I can’t imagine anybody objecting to the argument that you would have the moral authority sufficient to intervene on her behalf. Indeed, most would argue that you would have a duty to do so.

Though the woman could not explicitly solicit your assistance, your use of violence to defend a victim against an aggressor is justified and praiseworthy. Her status as a victim, especially when unable to call for aid, means that those with the ability to intervene are implicitly delegated the authority to do so, operating upon an extension of the victim’s own right to self-defense. This is very similar to the doctrine of “implied consent” for emergency responders, who are justified in assisting and even invasively operating upon an individual unable to verbally consent to the treatment.

Again, few will object to this claim. We generally feel justified in helping a victim when and where we are able to do so. But can this example scale up to geopolitical conflict and retain its relevance? In short, can we go to war to defend a victim nation from being attacked by an aggressor nation?

The answer, I believe, depends on who the “we” includes.

I am justified in defending a victim—a justification not bounded by geography. In other words, I can assist a woman being abused fifty feet away from me, or an Egyptian Coptic Christian being exterminated half a world away. Similarly, I can render aid by sending money or supplies to the victims, or my friends and I can pool our resources and employ somebody to help. If the “we” refers only to individuals who voluntarily and explicitly become a “Good Samaritan,” then the ensuing violence is justified as an extension of the victim’s implied delegation of authority.

This doesn’t happen because the “we” in our day refers to militaries coercively funded by taxpayers. Thus, using the American military (for example) to help the Jews or the Iraqis or the Syrians or any number of other victimized groups entails forcing all individuals within that nation’s jurisdiction to assist. Even though it may be a noble cause, those participating cannot morally be forced to do so.

Let’s take it back to the example on the street. While I would be justified in going to the abused woman’s aid, I would not be justified—whatever my reason, be it cowardice or indifference or efficiency—in pointing a gun at the head of another passerby, coercing him into helping the woman. This latter relationship lies at the heart of the modern military machine.

“That’s not practical!” the critic will say. Surely, the critic will similarly argue, the holocaust would have persisted without a strong show of force by Western militaries countering Hitler’s offensive. This alone, in the minds of many, justifies sending the military to the rescue. The end justifies whatever means deemed necessary to reach it.

But our original question sidesteps claims of practicality. We’re not asking how best to dethrone despots. We’re asking how, or if, we are morally justified in using violence to help others in need.

Even so, the practical argument is worth pondering momentarily. The American military (or any military) does not have unlimited resources. It is not comprised of an infinite number of individuals. It cannot be everywhere; it cannot rescue every victim. Thus, priorities are determined and decisions are made—even operating under the belief that the military can and should help victims requires ignoring the plight of the majority of victims while focusing on a minority.

Taking it a step further and saying that the military should help no foreign victims is a different argument—an extremely controversial one. In arguing this position we run the risk of appearing callous and cruel by acknowledging the unfortunate reality victims will suffer and die every day without somebody to help them. Too many individuals believe that you are unjustly condemning others to an unnecessarily early death unless you do everything in your power to prevent it.

But ends do not justify means. The existence of evil does not imply that one may do whatever is necessary to stop it. We are, and should be, bounded by rules that determine in which circumstances we may employ violence.

I believe that militaries are in too many instances unable to confine themselves to a noble cause. Innocent people are swept up into the conflict, and their deaths are dismissively classified as collateral damage. Disproportionality leads to “shock and awe” in which the attacks are escalated, broadened, and relentless. Vengeance begins to poison the hearts of all involved. And regardless of which wars they are engaged in, and who they are killing, all taxpayers are forced to fund their operations. In this fashion, hundreds of millions of people are made to be complicit.

No, voluntary armies would not be effective. Yes, many victims would continue to suffer and die without “humanitarian” military interventions worldwide. These and other points of concern are secondary and ultimately irrelevant to the question of morality. And after decades of constant conflict, the world could use an open and sincere discussion regarding the moral basis of military conflict—even and especially when done in the name of the oppressed.