From Wikipedia, the non-aggression principle (NAP) is a ethical stance held among right-libertarians that forbids acts of ‘aggression’ against one’s property rights. Somewhat confusingly, the NAP seems to have many definitions and variants:
1961 Ayn Rand In an essay called “Man’s Rights” in the book The Virtue of Selfishness she formulated “The precondition of a civilized society is the barring of physical force from social relationships. … In a civilized society, force may be used only in retaliation and only against those who initiate its use.”
1963 Murray Rothbard “No one may threaten or commit violence (‘aggress’) against another man’s person or property. Violence may be employed only against the man who commits such violence; that is, only defensively against the aggressive violence of another. In short, no violence may be employed against a nonaggressor. Here is the fundamental rule from which can be deduced the entire corpus of libertarian theory.” Cited from “War, Peace, and the State” (1963) which appeared in Egalitarianism as a Revolt Against Nature and Other Essays
Natural Rights: Some derive the non-aggression principle deontologically by appealing to rights that are independent of civil or social convention. Such approaches often reference self-ownership, ethical intuitionism, or the right to life. Thinkers in the natural law tradition include Lysander Spooner, Murray Rothbard, and Robert Nozick.
This suggests the NAP is sometimes interchangeable with the ‘golden rule’. As stated by Rothbard, defensive or retaliatory force should be commensurate with the force initiated by the aggressor. Thus it’s entirely within one’s discretion to engage in lethal fire against an intruder and or if one’s life is threatened, but not against targets that did not initiate sufficient aggression to justify a potentially lethal response. ‘Aggression’ can also be defined to mean coercion or force against property owners by entities such the government, an example being the IRS. The latter definition is descriptive wheres the former is prescriptive.
NAP as applied to deontological libertarianism seems to have a blind spot, which is how to deal with individuals that impose a collective or systemic burden on society but are not acting ‘aggressively’. Yes, if someone is threatening your life, lethal retaliatory force is justified, but what about small-time criminals, the mentally ill and unstable, loafers, and other ne’er-do-wells? The NAP, in the prescriptive sense, forbids simply rounding up all the unproductive and executing or exiling them all, as that is disproportionate ‘aggression’ against one’s right to life (natural rights) even if said individuals, individually, impose small externalities on society but collectively exact a significant burden.
For example, consider shoplifting, which is a very common and often non-aggressive crime that costs retailers, collectively, billions of dollars a year, and imposes a greater cost on society in terms of retailers passing on the costs of ‘shrink’ on to consumers. Obviously this is a big problem, and although most thefts are only around $50-100, when done many times by thousands of people, it adds up.
So how would a hypothetical libertarian or an-cap society that adheres to prescriptive NAP handle this problem. I imagine under NAP, the shopkeeper would exhort the thief to return the goods, possibly with the threat of physical violence for non-compliance, and the thief would probably comply knowing that there would be no long-term consequences for his actions and that getting caught is just a ‘cost of doing business’. Upon leaving the store, the thief continues to hit up more stores, occasionally getting caught, but it’s only a small setback, as there are no major repercussions for the thief besides the temporary inconvenience of having to relinquish the goods when occasionally caught. Stores don’t have the infrastructure nor want to bear the cost of warehousing thieves, and NAP stipulates violence is not an option for small violations of personal property. Also, some employees would probably have trepidation about exacting potentially lethal force to deter theft.
At some point having had enough, shopkeepers will band together, perhaps pooling money to create a facility to deal with these scoundrels in a manner that is sufficiency humane in compliance with NAP – in other words, a jail. But the problem is these reprobates, by in large, are unproductive and unwilling to work, and prison labor is not an option for most, and even if it were it’s not enough to cover the costs of housing them, but it’s worth the cost anyway if it means fewer thefts and sequestration of the most most undesirable of elements from greater society. This effectively acts as a ‘tax’ that individuals and businesses voluntarily enter into, from a utilitarian perspective, for the ‘greater good’ but also for the sake of their own profit margins and safety, with the prison becoming a ‘public good’, not a private one. Even if these prisons were privately run, business and individuals would still pay into them, effectively acting as a tax, the only difference being that it would be voluntary.
But then this is not ‘true’ libertarianism or an-cap. However, there are ways around this, such as by keeping ‘public goods’ as small and efficient as possible, and only when necessary, and possibly elective (meaning that one can ‘opt out’ of a public good). But the thing is, most self-professed libertarian and an-caps are only ‘partial libertarians‘ (similar to minarchism, as expounded by Nozick, Rand, Rothbard, and Hans Hoppe), and I don’t means this pejoratively, as the dilemma above suggests, may be the optimal approach of balancing individual rights with the ‘common good’. Interestingly, while there are ‘true’ neocons, neoliberals, and paleocons, it’s hard to find ‘true libertarians’.