For the half-century or so of the modern libertarian movement, the dominant conception of libertarianism – as shaped by the strong influences of Ayn Rand, Murray Rothbard, and Robert Nozick – has been based on natural rights. In this conception, individuals possess certain moral rights – to self-ownership and ownership of property – that exist separate and apart from any decision by a government to recognize and uphold them. Protection of these rights is the only legitimate use to which authorized force can be put. When authorities use force to protect rights, they are merely acting as agents of individuals to secure their right of self-defense; when authorities use force for any other purpose, they are violating rights and acting illegitimately. This line of thinking leads to the radical conclusion that only a minimal “night watchman state” or full-on anarcho-capitalism can satisfy the requirements of justice.

Among libertarians today, advocacy of minimal or nonexistent government in the name of defending natural rights is considered the “pure” libertarian position. Any deviation from that line, any qualifications or exceptions, represents a watered-down or compromised version of our political faith. Libertarian intellectual rigor is thought to consist of following natural rights premises to their logical conclusions regardless of how at odds with conventional wisdom those conclusions may be. The more rigorous the libertarian, the more willing he is (and yeah, it’s usually a he) to bite the bullets of hard cases – say, whether there should be laws against blackmail, or against cruelty to animals.

In this essay, I want to explain why I believe that libertarian natural rights radicalism is an intellectual dead end. In doing so I will take a different tack than the usual critiques from non-libertarians. The most obvious objection to radical libertarianism is that many of the specific conclusions it reaches are utterly repugnant to the overwhelming majority of people. The prospect of ending all tax-supported financing of education, care for the poor, and support for the elderly, or of abolishing all health, safety, and environmental regulations, strikes almost everybody as horrific, not too good to be true.

This rejection of radical conclusions makes practical objections to the intellectual framework of natural rights: followed too scrupulously, it will lead to bad results. Of course, radical libertarians have answers to those objections – answers that at least satisfy them. They see such practical criticisms as short-sighted, even pusillanimous – the same kind of nay-saying one would have heard many years ago in defense of divine-right monarchy or human slavery. Just as those institutions were once universally supported but have since been consigned to history’s dustbin, so too will the arc of moral progress eventually bend away from the modern welfare and regulatory state (and perhaps the state altogether).

Here I want to offer a deeper, intellectual objection to natural rights radicalism – namely, that the conclusions radical libertarians reach about the proper use of authorized force do not follow logically from their natural rights premises. The concept of natural rights is simply too open-ended, too indeterminate, to bear the burden that radical libertarians expect it to carry. Let us stipulate at the outset, for purposes of argument, that all human beings have a natural right of self-ownership as well as a natural right to own property acquired either through Lockean-style homesteading or voluntary exchange. From that starting point one can admittedly get to radical Libertopia, whether minarchist or anarcho-capitalist, but many other destinations are possible as well. Entirely plausible interpretations of natural rights can lead just as easily to a big welfare state and restrictive regulatory state.

Here I don’t mean to disparage the concept of natural rights, which is an important part of the liberal intellectual tradition. Of course there are sources of moral authority outside the state and by which state actions can be judged – this is the essence of the claim that there is a “higher law” to which we owe our ultimate allegiance. This idea is the patrimony of all liberals, not just classical liberals and libertarians: consider, as just one case in point, Martin Luther King, Jr.’s “Letter from Birmingham Jail.” More specifically, the idea of a system of compossible natural rights – according to which individuals have the moral right to make their own choices in life so long as they don’t interfere with others’ right to do the same – provides liberals of all kinds with an ideal model of human interaction. Individuals flourishing in lives of their own choosing through voluntary, positive-sum cooperation with others – that is the liberal ideal of the good society, and a system of natural rights provides its underlying moral structure.

The problem lies not with the concept of natural rights, but with that concept’s overextension. Although the idea of natural rights does provide basic principles for the legal order of a free society, those basic principles are indeterminate with respect to many of the most important issues that any working legal order has to resolve. In other words, it is impossible to derive a full-blown, operational legal order from these first principles.

I have argued this point in a previous essay for Libertarianism.org on the “nonaggression principle,” or NAP, which many libertarians point to as the basis for natural rights. In that piece I reviewed various specific legal issues – the alienability of land, what constitutes a nuisance, standards of liability, the rights of children, remedies for rights violations, and so on – for which there are no determinate answers. Here I want to examine similar ground but from a different angle. Specifically, I want to identify some of the broad, thematic questions of social order that must be resolved in translating natural rights into positive law.

Security of Rights versus Freedom of Action

The institutional structure of radical Libertopia focuses not on freedom, but on rights. Freedom of action is the residual left over after security of persons and property is established. Figure out first where everybody’s noses begin, and the scope of the right to swing your arm freely follows from that.

The big unanswered question is: just how secure should personal and property rights be? Or, in other words, just how much freedom should be permitted? The greater the security against harm that is granted to persons and property, the narrower is the scope to act freely. Depending on how these tradeoffs are managed, Libertopia could end up with much less freedom for its residents than its current champions would like.

The tradeoff between security of rights and freedom of action can also be seen as a conflict of rights: the right to secure and unmolested possession of one’s property, on the one hand, and the right to make active and productive use of one’s property on the other. Both, of course, are part of the bundle of rights that come with ownership of property, but these rights frequently come into collision. Resolving the conflicts requires value judgments about the relative importance of these two elements of the bundle.

These conflicts arise regularly with respect to issues of liability – that is, when the question is whether rights are being violated. For example, consider nuisances – unwelcome matter, noise, or light coming from someone else’s property. At what point do these physical trespasses (of effluents, sound waves, or photons) become legally actionable? If the threshold is set low enough, landowners will be highly constrained in what they can do on their property. Indeed, under an entirely plausible reading of nuisance law, industrial civilization would be basically impossible – imagine if any polluting activity, no matter how trivial the external effects, could be enjoined. Meanwhile, if the threshold is set high enough, landowners will be highly vulnerable to noxious and dangerous interference from their neighbors.

Or think about the imposition of risk – activities that endanger other people’s lives and property but have not yet caused harm. Let’s say your neighbor is conducting chemistry experiments in his garage that could wipe out the whole block in the event of an accident. Can you go to court and get an injunction to stop him? Or will the judge tell you “no harm, no foul”? In the former case, your neighbor’s freedom has been narrowed; in the latter case, your security from harm has been seriously compromised.

And what about the standard of care we owe to third parties? Are we liable for every harm we cause to others even if we did nothing wrong or blameworthy? Here again, there is no way to settle these questions without squeezing somebody: either some people’s freedom will be restricted or other people’s rights to life and property will be less secure.

The same conflicts also extend to issues of remedies – that is, deciding the proper legal response to rights violations. When an ongoing legally actionable harm is being committed, should the responsible party be ordered to desist or is an order to pay money damages acceptable? And when damages are awarded, should the responsible party have to pay for all resulting costs, however remote, or something more narrowly defined (e.g., damages that were foreseeable at the time the harm was committed)?

Consider, for example, a railroad whose trains create sparks when they travel, occasionally causing fires that cause significant damage to other people’s property. How to protect those property owners from these violations of their rights? If the railroad is merely required to pay money damages for the harm it causes, property rights along the rail line are not fully secure. It is known that the railroad is regularly causing property damage, but the authorities don’t do anything to stop it. In this situation, other people’s property rights are not a bar to rights-violating actions; they are merely a cost of doing business. The railroad is free to keep running its trains and starting fires so long as it pays the tab.

The security of rights, and by implication the scope of permissible freedom, can thus hinge on the choice of remedies for rights violations. With money damages, the railroad’s freedom of action is prioritized over the security of property rights along the rail line. If those property rights are made more secure – through the availability of injunctive relief to stop operation of the railroad, or imprisonment of the railroad’s executives for the harm they have caused, or perhaps even the death penalty for those executives – freedom will be much more narrowly circumscribed as a result.

And if it is decided that money damages are appropriate, further questions remain to be answered. How far must the railroad go in paying for the harm it caused? At the least, crops damaged by fire should be paid for. But if a workman hurts his back putting out the fire, should the railroad pay for years of treatment for pain? How about the pain and suffering of the workman’s spouse after the back injury renders marital intimacy impossible? How about the pain and suffering of the kids after their parents divorce? The farther the duty to pay is extended, the more constrained active users of property will be in doing anything that could result in crippling losses. And, consequently, the more secure neighbors will be in the quiet enjoyment of their property.

It is apparent, then, that there are wide possible variations on the common theme of a rights-protecting social order. When modern-day radical libertarians picture such an order, they imagine something that represents only a narrow slice of the available options. Specifically, they imagine an order in which some people, notably entrepreneurs, are granted wide freedom of action to the detriment of other people’s security of rights. That is one possible interpretation of how best to protect rights, but by no means the only one.

One can imagine a dramatically different social order in which the rights of all people to secure persons and property are treated as inviolably sacred. Other people’s rights are never thought of as a cost of doing business; rather, they are an absolute bar on violating conduct. In such a society, even relatively small risks of harm may be considered impermissible; accordingly, activities that create such risks are legally barred by preventive regulation. In a society that bends over backwards to ensure that rights violations occur as seldom as possible, there is very little room left for freedom.

It might be objected that the option of preventive regulation is foreclosed by the very idea of individual rights. According to the libertarian understanding of rights, it is impermissible to initiate force against anyone; force is allowed only in retaliation against violations of rights. If a regulatory agency were to fine or imprison someone for violating a preventive regulation (say, a rule that nuclear power plants conduct monthly safety drills), but that violation did not actually result in physical harm to anyone, then the regulatory agency would be initiating force in violation of the plant owner’s rights. This objection, however, does nothing more than beg the question. What constitutes initiation of force turns on what constitutes a violation of rights – which is the very thing that is in question here. It is entirely plausible to determine that, above some threshold, imposition of the risk of harm constitutes a violation of rights. If so, then preventive regulation violates no rights because nobody has the right to impose the proscribed risks.

None of the issues I’ve discussed here are idle hypotheticals: these questions all arose during industrialization, and how they were resolved had a decisive impact on economic development. During the first half of the nineteenth century, many important doctrines of American private law (the law of property, contract, tort, and commercial dealings) were altered as judges rewrote the rules of the game to make them more conducive to industrialization. Among the more important doctrinal innovations: use of the “public nuisance” doctrine to prevent private suits against activities that caused widespread harm throughout a community; a shift from strict liability to a negligence standard; judicial control over damage awards to ensure their greater certainty and predictability; and the doctrine of “negotiability” to make debt instruments tradeable regardless of defects in the chain of title.

In making these sweeping changes, judges weren’t merely “finding” the law according to some value-free rule of reason. On the contrary, they were actively making law. They didn’t do so because they were usurping power; they did so because they had to. The concept of natural rights may instruct us to protect individual rights, but it is silent as to how much protection they should receive. That choice remains wide open, and depending on how it is exercised the character of the legal order can vary dramatically. If freedom of action is strongly privileged over security of rights, you can get to Libertopia as it is imagined by contemporary libertarians. If, however, the sanctity of rights is upheld, the result can be a highly restrictive regulatory state.

Rationalism versus Pluralism

In his recent book Rationalism, Pluralism, and Freedom, McGill University political theorist (and Cato Institute adjunct scholar) Jacob Levy identifies two conflicting strains within liberalism: rationalism, or the belief that rights are best protected by a common set of rules applicable to all; and pluralism, or the belief that the best guarantor of liberty lies in the proliferation of intermediate groups (families, religious organizations, voluntary associations) that protect individuals from potentially overweening central authority. Levy concludes that these two strains are ultimately irreconcilable: ensuring equal treatment for all and ensuring free association are in fundamental conflict, and threats to liberty can come both from above (the central authorities) and from below (private aggression). An uneasy shifting balance between the two strains is therefore the best we can manage.

The ongoing tension between rationalism and pluralism highlights a basic conundrum of establishing and maintaining a free society: the protection of individual rights requires some authority powerful enough to subdue local rights violators, but any authority sufficiently powerful is itself a grave potential threat to liberty. As James Madison put it in Federalist no. 51: “In framing a government which is to be administered by men over men, the great difficulty lies in this: you must first enable the government to control the governed; and in the next place oblige it to control itself.”

Levy’s analysis suggests that the choice of remedies for rights violations is always a tragic one.

Threats to liberty come from two opposite directions – above and below – and remedies that focus on reducing rights violations from one direction will inevitably work to increase risks of rights violations from the other direction. There is no possibility of a final equilibrium in which a stable set of institutions applying unchanging laws protects all people’s rights equally.

The seriousness of this problem is underscored by the fact that radical libertarians cannot even agree on the most basic institutional features of Libertopia. Here I am referring to the split between advocates of a minimal state and advocates of anarcho-capitalism. Both sides argue that the other side’s position is impractical and unworkable. Minarchists contend that private security firms will degenerate into mafias; anarchists respond that the minimal state will gradually transform into Leviathan. Whatever you make of the relative merits of their arguments (I think both sides make good points!), it’s clear that the best institutional structure cannot be deduced from reason alone. Indeed, Levy’s point is that there is no such thing as the best institutional structure. This indeterminacy applies not just to the choice between a state and no state, but also to the choice of kind of state. Thus the appeal of ideas like federalism and subsidiarity turns on whether one is more worried about threats to liberty from above or below.  

Moving beyond remedies to questions of substantive rights, the conflict between rationalism and pluralism is most apparent with respect to the rights of children. Parents regularly force their children to do things they don’t want, from eating their vegetables to enduring parental discipline to undergoing circumcision or a clitoridectomy. At what point does such coercion violate children’s rights? And when it is appropriate for the authorities to step in and intervene? Meanwhile, it is generally (but not universally!) conceded that parents have a duty to care properly for their children – not just refraining from injuring them, but providing them with food, clothing, and shelter. How exactly is this duty enforced? And, as times change and the requirements for participating constructively in society change, do the affirmative duties of parenthood expand as well?

These questions become especially pressing when the parental practices in question occur in the context of cultural communities with illiberal values – think traditionalist religious groups or newfangled cults. The children in those communities clearly didn’t choose to be there, but are there circumstances short of physical and sexual abuse that would warrant their forcible removal by the state? What about adults who grew up in those communities, isolated from outside influences and ignorant of their rights? Under the circumstances, how valid is their consent to, say, arranged marriages or being beaten by their husbands when they disobey?

How much intolerance to tolerate is a question with no easy answers but potentially immense consequences. Too much laissez-faire could allow illiberal cultures to spread to the point that support for the libertarian polity collapses; too much intrusion by the authorities into the intimate connections of family, faith, and community could likewise spark an anti-libertarian backlash against “outside agitators.”

In an article entitled “Two Constructions of Libertarianism,” London School of Economics political theorist (and Cato Institute adjunct scholar) Chandran Kukathas explores just how divergent the plausibly libertarian answers to this question can be. He imagines two societies, the Federation of Liberty and the Union of Liberty, that both recognize the libertarian nonaggression principle. In the Federation of Liberty, non-libertarian communities are allowed to exist unmolested so long as their members do not commit aggression against anyone outside their communities. The authorities will protect the rights of members of non-libertarian communities only if they have expressly designated the authorities to act as their agent. In the Union of Liberty, by contrast, full libertarian rights are protected for all members of society. Indeed, no organization that in any way impinges on those rights is allowed unless all its members expressly waive the rights being restricted. At these poles of pluralism and rationalism, respectively, there are serious risks of widespread unfreedom. In the former, tolerance of intolerance creates the possibility that unfreedom will spread from below; in the latter, the strong central authority needed to enforce rights universally creates the possibility that the authority will morph into Leviathan and spread unfreedom from above.

There is no final resting point between these poles. Freedom always exists on a slippery slope. Natural rights cannot deliver us to solid ground, because solid ground doesn’t exist.

Righting Past Wrongs

In his Second Treatise of Government, John Locke famously set forth how property rights can emerge, as it were, by immaculate conception – that is, without any rights-violating aggression. When people mix their labor with objects in the state of nature, they create property where none existed before; thus, they take something without taking it from anybody.

This idea is foundational for radical libertarians: Lockean homesteading, when combined with freedom of exchange, gives them the basic outline of the system of natural rights whose protection is the sole acceptable purpose for the authorized use of force.

But there’s a problem: even though it is possible in theory for property rights to arise and be transferred without aggression, that possibility has little to do with the actually existing distribution of rights over land and material objects. Here in the real world, virtually all chains of title trace back to armed conquest and plunder. In the United States, expropriation from Indians and aggressive wars figure prominently in the story. As for the England of John Locke, Thomas Paine offered this withering assessment of one important source of rights over real property there: “A French bastard landing with an armed Banditti and establishing himself king of England against the consent of the natives, is in plain terms a very paltry rascally original.”

According to radical libertarian theory, a just social order is one in which all legal entitlements derive from homesteading and peaceful transfer. Alas, in our fallen world no such social order can be found anywhere. Yet radical libertarians today generally hold that governments should affirm and protect the current pattern of property holdings and that any redistribution of property by government is illegitimate. What gives?

At issue here is when to wipe the slate clean on past injustices. Implicit in the prevailing libertarian position today is that injustices sufficiently remote in time can be ignored. It is a sensible position: the common law features many doctrines that favor legal certainty over the claims of justice (e.g., the rule of adverse possession, under which squatters gain title over abandoned land after 21 years of uncontested possession), while in the criminal law statutes of limitation serve the same purpose. Yet different rules apply in other circumstances. For example, an unwitting purchaser of stolen property (e.g., a work of art) can be required to return that item to the original owner even after decades of uncontested possession. You can make plausible arguments either way: how long valid claims of right persist in time cannot be deduced logically from the concept of natural rights. Here again, natural rights are indeterminate.

It is certainly possible to argue that proper regard for the sanctity of rights means that past injustices cannot be ignored. In an ingenious article entitled “Libertarianism at Twin Harvard,” University of Virginia political philosopher (and Cato Institute adjunct scholar) Loren Lomasky imagines an alternate universe with a Twin Earth and a Twin Harvard University. Twin Harvard, like the one here, was home to a pair of famous political philosophers named John Rawls and Robert Nozick. But in that alternate universe, Twin Rawls used his updating of social contract theory to argue for a robustly libertarian vision of justice, while Twin Nozick argued on natural rights grounds for a massive redistribution of wealth.

Lomasky’s account of Twin Rawls is very much worth reading, but it is Twin Nozick’s thinking that is of interest here. On our Earth, Nozick’s Anarchy, State, and Utopia addressed the subject of past injustice only briefly. He recognized that past injustice undermines the justice of current holdings and then speculated briefly about a possible “principle of rectification” that would specify exactly how existing holdings need to be altered. Having raised the issue, however, he declined to consider it further.

Twin Nozick, however, continued to pull on this string and found there is no available principle of rectification. According to Lomasky, “there can be no hope of unraveling the tangled skein of injustices so as to place things in the hands where they properly belong.” The dead are beyond the reach of justice; many born today would not even exist but for past rights violations. “In so convoluted a moral realm,” Lomasky continues, channeling Twin Nozick, “there is nothing for the entitlement theorist to do other than throw up her hands and admit that Humpty Dumpty is not to be put back together again.” Accordingly, the best that can be done is for Libertopia to be instituted only after a complete redistribution of property so that all begin the new order with equal holdings. As Lomasky puts it, “First the time of Tribulations, and only then the Millennium.”

All of this is so far removed from practical reality that it seems fanciful. But consider the real-world example of African-Americans: a group of people brought to this country in chains, enslaved for centuries, systematically oppressed by a combination of state and private violence for another century, and then finally elevated to formal legal equality just a half-century ago (although still to this day denied substantive equality of treatment by government, especially with respect to law enforcement and schooling). Since the end of Jim Crow, libertarians have generally been harshly critical of any policies designed to provide any kind of compensation (whether restitution or affirmative action or otherwise) to African-Americans – even though explicit legal oppression had just been ended and the actual victims of that oppression remained alive. In taking that position, libertarians might have thought they were making a principled defense of individual rights – but if so they were mistaken, as the concept of natural rights is indeterminate with respect to the matter. The prevailing libertarian hostility to compensatory policies of all kinds has been a policy choice, plain and simple – and one with unsurprising consequences in terms of African-American receptivity to libertarian ideas.

Necessity and Redistribution

Unremedied past injustices may make the case for a one-off redistribution of resources, but what about ongoing redistribution? We have already seen that a highly restrictive regulatory state can be consistent with the protection of natural rights. Can the same be said for a welfare state?

The doctrine of “necessity” in common law provides paths to an affirmative answer from a couple of different angles. First of all, in exigent circumstances individuals may have the right to commandeer others’ property to save themselves: a famous case involves a boat owner trying to use someone’s dock during a bad storm. The logic of this exception is fairly compelling. Although theorists have sought to derive natural rights in many different ways, it is generally held that the recognition of others’ rights is rooted in humans’ rational faculty. But, faced with death or serious loss, what reason could anybody have for respecting others’ ownership rights?

It doesn’t take too much in the way of mental gymnastics to apply this exception generally to the exigent circumstances of poverty. Indeed, Loren Lomasky has made a natural-rights-based argument for limited positive welfare rights on these general grounds.

In this take on necessity, we see another permutation on the tradeoff between freedom of action and security of rights. When it comes to entrepreneurs undertaking projects that they know will cause injury and property damage, libertarians are sympathetic to legal rules that privilege entrepreneurs’ freedom of action over third parties’ security of rights. This time, though, the sauce is for the gander: now it the poor’s freedom to secure basic sustenance that trumps others’ property rights at the margin (that natural freedom translated into positive law as a system of state-provided assistance).

Even if the case for affirmative welfare rights is rejected, the doctrine of necessity points to another justification for redistribution – namely, as a defensive measure to protect property rights when large numbers of people in the society are too poor to feel they have a stake in the property rights system. The common law analogy here is found in cases when the government has to destroy some people’s property to save others’ – say, demolishing a building to create a firebreak during an urban conflagration.

This argument for redistribution – as a necessary expenditure to secure property rights against internal uprisings and revolution – has significant support in the historical record as well as contemporary social science. Thus, Stanford economic historian Avner Greif, together with coauthors, has shown that the early modern English system of state-provided poor relief, by reducing riots and other violence, played an important role in midwifing the Industrial Revolution. One specific finding of note: English counties that spent more on poor relief experienced fewer riots and more innovation as measured by patents. Meanwhile, economists Daron Acemoglu of MIT and James Robinson of University of Chicago have argued that the extension of the franchise in nineteenthcentury Western countries – and with it the political power to vote for ongoing redistribution – constituted a tactical retreat by governing elites threatened with widespread social unrest and possible revolution. And in the present day, is it just a curious coincidence that the countries that now boast the most secure property rights and most robust economic freedom are the Nordic countries best known for their extensive welfare states?

This application of the doctrine of necessity is just another example of the tradeoff between limiting coercion from above and limiting it from below. In order to head off the threat of revolution (i.e., coercion from below at its most destructive), it may be necessary to grant government additional powers – namely, to tax some and spend on others. Radical libertarians typically regard any such redistribution by government as a violation of taxpayers’ rights. It is, however, entirely plausible to understand redistribution as rights protection: under circumstances in which people at the bottom do not see the system of property rights as working for them, some kind of welfare state may be an indispensable part of keeping property rights as secure as possible.

The Outside World

The defensive case for redistribution resolves a problem that radical champions of Libertopia tend to assume away: how do you best protect natural rights when not everybody (or, more realistically, almost nobody) is a libertarian? There the issue concerns internal opposition – people living under libertarian rules who do not believe those rules are working out well for them. But similar problems emerge with respect to the outside world. Assuming that someday, somewhere, a polity along the lines favored by radical libertarians could be established, how would it handle threats from beyond its borders?

Of paramount importance is the issue of national defense. In a regime of pure rights protection, how does one protect that regime from invasion by hostile foreign governments? Here the familiar tradeoff between security and freedom can be especially stark – and agonizing. Eschew as unlibertarian the protections afforded by a standing army, alliances, or forward placement of troops in buffer states, and Libertopia may cease to exist because of a foreign invader. Embrace those protections, and Libertopia may cease to exist as it eventually transforms into Leviathan.

The question of immigration can also be a vexing one. All human beings, not just the inhabitants of Libertopia, possess natural rights, and among them is the right is live wherever you choose (provided, of course, someone is willing to sell you housing there and you can find employment to support yourself). Yet the continuing security of individual rights in Libertopia is ultimately dependent on the political opinions of the people living there: unless some critical mass of the population remains libertarian, the authorized use of force will not stay within the bounds set by the polity’s founders. Accordingly, allowing too many immigrants from countries with unlibertarian political cultures could mean allowing them to bring Leviathan with them. Once again, respecting some people’s rights can require putting other people’s rights at risk, and there is no neutral principle for resolving the conflict.

Conclusion

Radical libertarians imagine that they have found in natural rights an impregnable intellectual fortress for defending their vision of minimal or nonexistent government. Regardless of the relative weight of empirical evidence about the effects of this or that government policy, they can rest assured in the belief that they are correct on moral grounds. All the endless back-and-forth of ultimately inconclusive social science is really beside the point: any government actions that go beyond simple rights protection are illegitimate and unjustifiable. Case closed.

Yet on closer inspection, it turns of that the libertarian fortress of natural rights isn’t so impregnable. On the contrary, at one critical juncture after another this intellectual structure is porous with ambiguity. Even granting that protecting natural rights is the only legitimate use of authorized force, big questions of fundamental importance remain open. In the discussion above, I identified five such questions. How should we balance freedom of action and security of rights? How should we balance the risks of unfreedom from above and those of unfreedom from below? How should we deal with past injustices? To what extent is the most complete possible protection of rights shaped by necessity – in particular, the demands of the poor and disaffected who have no stake in the system? And how should we deal with the outside world?

More sophisticated presentations of radical libertarianism do take note of some of these complexities. However, they present these open questions as minor blank spaces in an otherwise determinate legal structure, to be filled in by custom or common-law jurisprudence. But the questions to be answered in translating natural rights into positive law are anything but minor. Depending on how they are answered, radically different social orders can result.

The impregnable fortress is a fantasy. There is no necessary connection between full commitment to Lockean-style natural rights and the minimal/zero government vision of radical libertarians. That vision supplies merely two of the many and wildly various options, including restrictive regulatory states and expansive welfare states. The idea of individual natural rights has fairly clear implications regarding freedom of speech, conscience, and assembly, and freedom of person and property from arbitrary seizure. But in the realms of social policy and economic regulation, the power of natural rights to shed light on resolving details of policy and positive law is limited. More widely shared considerations – such as effectiveness, efficiency, and consistency with economic and political constraints – have more power in defining limits to government power that libertarians find congenial, if not completely satisfying.

The indeterminacy of natural rights is a heavy blow to the whole radical libertarian project. If the minimal/zero government vision is no longer uniquely aligned with the clear demands of justice, what could persuade anybody to adopt a political creed whose departures from consensus opinion are so numerous and extreme? It is, of course, possible to argue for Libertopia on consequentialist grounds, as libertarians frequently do. But without the moral trump card of natural rights to undergird and reinforce them, those consequentialist arguments don’t pack much persuasive force.

To be sure, the larger liberal intellectual tradition, including the modern social science of economics, provides powerful and persuasive support for stable property rights and competitive markets. There is a wealth of empirical evidence that shows relatively more market-oriented systems produce better results along many different margins than do more state-controlled economic systems. But radical libertarians are obligated to go beyond merely arguing for less regulation and lower levels of taxation and government spending; they must argue that a complete elimination of preventive regulation and tax-financed redistribution would improve welfare. But there is no convincing evidence for that proposition – first, because there are no real-world examples of such policies in modern times whose results can be evaluated and compared; and second, because there is plentiful evidence that government actions over and above protecting property rights can improve welfare relative to the laissez-faire status quo. Consequently, in the move from classical liberalism to radical libertarianism, the quality of consequentialist argument declines from the well-founded to the simplistic and dogmatic.

I believe the best path forward for libertarians is to abandon radical libertarianism’s intellectual muddle altogether. Instead of spinning utopias, libertarians should focus instead on the humbler but more constructive task of making the world we actually inhabit a better place. Freed from their illusory fortress, libertarians will find that the rich intellectual tradition of liberalism affords them ample resources to participate in crafting answers.