Only libertarianism can provide a robust justification for open borders

A growing number of philosophers and political theorists endorse open borders. In his seminal work on the topic, Carens (1987) argues that liberal egalitarianism justifies free international movement. Other political philosophers contend that libertarian, democratic, and utilitarian principles support open immigration as well. Pevnick (2014: 79) comments that “it is no exaggeration to describe open borders as the dominant position among academics writing about justice and immigration. Indeed, here it is any non-open borders position that is seen as so much fanciful provocation.”

Moreover, prominent historical and contemporary figures have defended the view that the right to immigrate is a human right—that is, a universal moral requirement that applies across cultural contexts much like freedom of speech or bodily autonomy. Douglass (1869), for instance, writes, “There are such things in the world as human rights. They rest upon no conventional foundation, but are external, universal, and indestructible. Among these, is the right of locomotion; the right of migration; the right which belongs to no particular race, but belongs alike to all and to all alike.” More recently, Oberman (2016) has made the case that the freedom to immigrate protects universal and weighty human interests and that these interests ground a human right to immigrate. ¹ The claim that immigration is a human right has been defended by a number of commentators in popular discourse as well. ²

Given the widespread support for free immigration among political philosophers, there must be powerful arguments in its favor. But what kind of political theory could provide an argument that vindicates immigration's status as a human right whose protection is morally required in nearly all circumstances? We argue that libertarianism—and only libertarianism—does. Indeed, Stilz (2019: 204) has recently criticized several prominent arguments for open borders on the ground that they appear to

rest on a libertarian conception of freedom, according to which any state restriction on our options is presumptively wrong. Such a broad view of freedom would render much ordinary state action (e.g. minimum wage or maximum working-hours limits, professional licensure requirements, and environmental or historic preservation laws) illegitimate. Many of these state actions also coercively restrict our options, but it is not obvious that they are unjustified.

We believe that a robust case for open borders does rest on a libertarian conception of freedom; however, we argue that this implies that one ought to raise one's credence in the plausibility of libertarian principles rather than lower one's credence in the plausibility of open borders.

Our case proceeds as follows. We begin by outlining the core tenets of libertarianism and their implications for immigration policy. Although we lack the space for a comprehensive review, we explain why two major competing views—utilitarianism and liberal egalitarianism—fail to provide a justification for open borders that is decisive in nearly all realistic conditions. After addressing objections, we conclude by suggesting that our argument strengthens the case for libertarianism rather than weakens the case for open borders.

Libertarianism

In this section, we’ll sketch one influential, rights-based version of libertarianism. We acknowledge that not all self-described libertarians would endorse the account we present here. However, we aim to describe what is perhaps the prevailing view among libertarian political philosophers. Moreover, it is this deontological form of libertarianism that is best suited to substantiate immigration's status as a human right. Other versions, such as consequentialist libertarianism, are only contingently committed to open borders (we’ll discuss the consequentialist case for open borders below).

By “open borders,” we are imagining a system that's similar to the borders between the different subunits in a federal system, such as the United States. There may still be minimal or nominal borders between states, but they would be extremely porous. ³ Does this mean that a libertarian state would admit absolutely anyone who wants to enter? For example, would it be obligated to admit terrorists or hardened criminals? Not necessarily. As we will discuss below, libertarian principles are consistent with restrictions on immigration if these restrictions are necessary to prevent sufficiently bad outcomes, such as terrorist attacks or other grave rights-violations. ⁴

Libertarianism is a member of the broader family of liberal views that claim justice first and foremost requires respect for individual liberty. ⁵ Libertarianism, like more egalitarian versions of liberalism, holds that people possess civil liberties such as freedom of speech, association, religious practice, occupational choice, and so on. Moreover, both libertarians and liberal egalitarians assign these liberties lexical priority (or something close to it) over competing values such as cultural integrity or distributive justice. As Rawls (1999: 4) claims, liberal rights “are not subject to political bargaining or to the calculus of social interests.”

Yet libertarians and liberal egalitarians differ in two critical respects. First, libertarians’ conception of basic economic rights includes the right to own productive private property and freedom of contract. ⁶ Liberal egalitarians such as Rawls (1999: 54) are explicit that their doctrines omit these rights from the list of basic liberties: “The right to own certain kinds of property (e.g. means of production) and freedom of contract as understood by the doctrine of laissez-faire are not basic; and so they are not protected by the priority of the first principle.”

Second, libertarians endorse a more extensive account of the scope of basic rights than liberal egalitarians. Here's Rawls again (1999: 12):

The basic rights and liberties and their priority are there said to guarantee equally for all citizens the social conditions essential for the adequate development and the full and informed exercise of their two moral powers—their capacity for a sense of justice and their capacity for a conception of the good.

Thus, Rawls does not endorse a maximally expansive account of the basic rights and liberties. Libertarians, by contrast, endorse a less restrictive principle—for instance, that one's rights to speak freely or dispose of one's property are limited only by the like rights of others. On this view, even “trivial” exercises of one's rights—that is, those that are not necessary for the development or exercise of one's moral powers—are protected.

In brief, libertarians believe that states have powerful reasons to respect individual rights, and these include extensive rights to acquire, use, and own productive private property and form contracts. These commitments put severe constraints on the exercise of state power.

Most famously, libertarians think that it's often wrong for states to redistribute private property even to benefit the disadvantaged. If people have robust rights to own property, then redistributing this property seems prima facie to violate their rights. Here's one way to understand this commitment. Libertarians tend to believe that state power is permissible only under the same conditions that a private actor's actions would be permissible. And normally it's wrong for private actors to coercively appropriate our private property and redistribute it to other people.

By way of illustration, consider an example adapted from Michael Huemer's The Problem of Political Authority (2013, chapter 1). Suppose that Bradley operates a charity organization that aims to benefit people in poverty in his neighborhood. The details aren't critical, but we might imagine that Bradley's organization provides direct transfers of income, subsidized education and healthcare, and other benefits to the poor in the neighborhood. But Bradley's organization is unable to raise enough funds to finance its programs. So, Bradley approaches his well-off neighbors and demands money from them. If the neighbors refuse to pay, then Bradley will regrettably need to imprison them in his basement. And, if they resist, Bradley will have to use physical force against them in order to appropriate their property.

Most would agree that what Bradley does is seriously wrong, even though it may be for a good cause. Crucially, libertarians deny that there's any intrinsic moral difference between what a redistributive state does and what Bradley does. Of course, there are contextual differences—state redistribution may be less sudden or unexpected, it may involve some opportunity for contestation and appeal, and so on. Yet these factors fail to differentiate state coercion from Bradley's actions at the level of basic moral principle. If Bradley's actions are wrong, then so is state redistribution.

Libertarians, then, tend to be skeptics about political legitimacy and authority. Political legitimacy is the permission to create and enforce rules over certain people within a geographic area. Political authority is the ability to create in others a moral obligation to obey those rules. ⁷ So, a government has political legitimacy and authority if it can permissibly create and enforce rules and those subject to these rules are obligated to obey those rules. Libertarians deny that governments have these properties. Although we lack the space to argue for this claim, we will note that it has been defended at length by libertarians elsewhere. ⁸

It's worth noting that libertarians aren't typically absolutists about rights—they acknowledge that rights may be overridden in exceptional circumstances. Imagine that a train is heading toward five children who are tied to the railroad tracks. Bradley can only save their lives by hotwiring his neighbor's car and interposing it between the children and the train. This seems like it would be all-things-considered justified, despite the fact that Bradley's actions violate his neighbor's property rights.

But libertarians insist that rights violations are only all-things-considered justified under strict conditions. For example, these violations must be necessary to prevent a much greater evil from occurring. And, just as these conditions apply to the conduct of private actors, they likewise apply to state action. So to justify state violations of rights, rights violations must be necessary to avoid some much worse outcome. ⁹

In summary, a standard libertarian position goes something like this: governments ought to protect rights foremost, these rights are extensive, they include rights to productive property and freedom of contact, and states can only permissibly override rights when state action satisfies stringent conditions. Thus far, we’ve done little to justify this libertarian position—we’ve only described it. We’ll return to the question of justification later; for now, we’ll examine how libertarian principles apply to the issue of immigration.

The libertarian argument for open borders

Libertarianism provides a straightforward argument for open borders: immigration restrictions violate the rights of both the citizens of a state that curtails immigration and foreigners who want to immigrate. People often want to form relationships and contracts across borders. Consider employment relationships. Suppose that Sandra wants to hire John to work in her business, and John would like to work for Sandra as well. But John happens to be a foreigner who lives in another country and Sandra's government forbids John from immigrating. In this way, immigration restrictions interfere with Sandra and John's consensual relationship. Or consider the impact of immigration restrictions on other kinds of relationships. Imagine that Sarah wants to rent or sell a home to Rebecca and Rebecca wants to accept this offer. Rebecca, however, is a foreigner. So, Rebecca is unable to occupy the home that Sarah is offering her.

In short, immigration restrictions prevent citizens and foreigners from associating with one another on their own freely chosen terms. Owners of businesses and housing possess a right of disposal over their productive property that entitles them to hire and rent as they see fit. Foreigners as much as citizens possess a largely unrestricted right of occupational choice and freedom of contract which entitles them to accept the employment and rental terms of their choice. And a largely unrestricted right of free association protects both citizens’ and foreigners’ liberty to marry and reside with the partners of their choice. If immigration restrictions violate these rights, then this constitutes a powerful objection to them from a libertarian perspective. Notice that the libertarian presumption in favor of free movement is grounded in the rights of foreigners and citizens. Immigration restrictions are presumptively unjust because they interfere with both the rights of citizens to associate with foreigners and foreigners’ rights to associate with the citizens of other states. ¹⁰

An objector might respond to this argument by claiming that states also have rights to freedom of association. Furthermore, states can exercise these rights by choosing to exclude potential immigrants. Individuals have a right of exit, given that they may not be forced to associate against their will, but not a right of entry, given that this right would imply that an association may be forced to accept a member against its wishes.

However, since states are nonconsensual organizations, libertarians are skeptical that states have rights to freedom of association that can weigh against the rights of individuals. To help motivate this claim, let's return to the example of Sarah and Rebecca. Imagine that Sarah wants to associate with Rebecca by inviting Rebecca to live in Sarah's house or by employing Rebecca in her business. But suppose that Sarah's neighbors dislike this arrangement and want to prevent Sarah and Rebecca from associating in this way. Sarah's neighbors claim: “our neighborhood has a right to freedom of association. Moreover, this right permits us to exclude Rebecca from the neighborhood.” Yet libertarians would deny that the neighborhood has a right to freedom of association that entitles it to prevent Sarah and Rebecca from associating. Things would be different if Sarah and Rebecca agreed to abide by the terms that their neighbors set. But let's assume that Sarah and Rebecca never consented to these terms. So, the neighborhood lacks a right to exclude Rebecca. According to libertarians, this same basic analysis applies to states. Libertarians generally hold that states lack rights to freedom of association that can compete with individual rights to associate with foreigners. ¹¹

Remember that libertarians generally believe that an exercise of state power is permissible only under the same conditions that a private actor's similar actions would be permissible. With this point in mind, consider a scenario that Huemer describes. ¹² Imagine that Marvin is starving. If Marvin is unable to find food soon, he’ll die. So, Marvin sets off for the local market in order to buy bread there. People in the market are happy to sell bread to Marvin. But another person, Sam, decides to stop Marvin from reaching the marketplace. Sam forcibly prevents Marvin from entering the marketplace. Consequently, Marvin returns home without food and he dies of starvation. Sam's behavior is obviously wrong. Why? One explanation is that Sam coerces Marvin in a harmful way. But let's also assume that the state may not do what it would be wrong for any nongovernmental person to do. Thus, if it's wrong for a private actor like Sam to subject Marvin to harmful coercion, then it's prima facie wrong for states to subject potential immigrants to harmful coercion too. In this way, libertarians’ skepticism of political authority and legitimacy grounds a strong presumption against immigration restrictions.

Moreover, libertarian principles rule out the sorts of theoretical reasons that philosophers and political theorists tend to offer in favor of immigration restrictions. For instance, some theorists argue that the state may restrict immigration to preserve important cultural values. But on a libertarian view, the state's interest in promoting “cultural integrity” does not override individuals’ rights to dispose of their property or associate freely. Just as a homeowner may rent their house to a tenant who disrupts the cultural integrity of her neighborhood, she may rent her house to a tenant who disrupts the cultural integrity of her nation. ¹³

Or consider the argument that states have rights to collective self-determination that permit them to restrict immigration. According to this argument, political communities have moral rights to shape their character and control their membership. This right entails that states are also entitled to restrict immigration. Libertarians reject this argument. To see why, notice that the character and membership of political communities are, to a large extent, the product of individual choice. People decide to adopt certain cultural norms or not, to have children (thereby introducing new members into the political community), and to engage in other patterns of behavior that alter the membership and character of the community. If states have rights to regulate and control their character and membership, then they have rights to control and regulate the peaceful, voluntary choices of their members. And libertarians deny that states have any such rights. Thus, they reject the claim that rights to self-determination permit states to control immigration.

Critics of open borders sometimes allege that increased immigration will diminish the wages and employment prospects of low-skilled domestic workers. However, to borrow a phrase from Nozick (1974: 163), libertarians contend that the state may not prohibit “capitalist acts between consenting adults,” even when such prohibitions have salutary effects on wage or employment rates. This is why libertarian institutions permit firms to outsource labor to foreign countries and workers to accept sub-minimum wage labor contracts.

Lastly, consider a common distributive justice argument for immigration restriction: the state is obligated to institutionalize tax-funded welfare programs to benefit the domestic poor, programs that are allegedly incompatible with open borders. Libertarians can make quick work of this objection, as they deny that coercive income redistribution is typically permissible. It's worth noting that many libertarians deny that coerced income redistribution is categorically prohibited; rather, they insist that the needs met by such redistribution must be sufficiently urgent. Huemer (2013: 152), for example, argues that you may compel another to spare a child from drowning, but not from being uncomfortable in cold weather. The point stands even if the cold child is someone to whom you owe special obligations, such as your daughter.

The upshot, in Huemer's view (2013: 153), is that “if the government is to institute coercive aid programs at all, it surely must direct its efforts toward people whose lives are in grave danger yet who could be saved at minimal cost rather than toward people with much less urgent needs that are much more expensive to address.” More specifically, this principle rules out most domestic redistributive programs; they tend to target needs that “are not sufficiently urgent to justify coercion. The need to save a person from death or serious injury may justify a moderate level of coercion and moderate violations of property rights. But the desire to supply a person with quality clothing, a college education, or an air conditioner typically does not suffice to justify coercive seizure of the necessary funds from innocent third parties” (Huemer 2013: 153). Thus, the state may, in certain circumstances, coercively enforce positive duties to the severe poor but rarely will this consideration justify domestic welfare states.

So, we may suppose, for argument's sake, that immigration undermines the welfare state in some important way. Libertarians would deny that this result furnishes a reason to restrict immigration because they deny that the welfare state is justified to begin with. The concern that immigration damages the welfare state would thus have little weight for libertarians.

To sum up, libertarian principles imply a strong presumption in favor of open borders. Moreover, standard arguments for immigration restrictions fail to override this presumption. Of course, it's possible that there's some other set of considerations that override the libertarian presumption in favor of free migration. In particular, some defenders of immigration restrictions pose an objection from extreme cases—for instance, may a state prohibit the entry of a billion foreigners to prevent its own destruction? What about a prospective immigrant who is carrying a lethal and contagious disease?

Recall that most libertarians believe that rights can be overridden given sufficiently weighty countervailing considerations. Even hard-boiled libertarians such as Nozick are willing to grant that rights may be compromised in extreme cases. Indeed, we think that any plausible theory will include a clause that suspends normal rights and duties to prevent a disaster. (What counts as a disaster is of course a matter of debate.)

But it's unlikely that many immigration restrictions are justified in order to prevent disasters. We’re unable to comprehensively defend this claim here, although we and others have discussed this issue in detail elsewhere. ¹⁴ Here's the key issue: it's unjust to violate rights only on the basis of speculation that such violations will prevent disasters. To justify immigration restrictions as a means of averting disastrous outcomes, we need to have strong evidence that immigration would have these consequences and we must also show that immigration restrictions are necessary to prevent them. This is a high standard of proof and we should doubt that this standard will often, if ever, be met. The evidence that open borders would generate disastrous outcomes is weak, and many standard concerns about the bad effects of immigration fail to withstand careful scrutiny. Libertarians would be skeptical about restricting the freedom to immigrate only on the basis of speculative evidence. ¹⁵

Furthermore, even if immigration would produce disastrous outcomes, it's unclear whether immigration restrictions are the appropriate remedy. When immigration generates harmful outcomes, there may be “keyhole” solutions to these problems, solutions that narrowly address these specific problems rather than prohibiting immigration in general. For example, if immigration dangerously strains the public finances of a state for some reason, this state could tax immigrants more rather than forbidding them from immigrating at all. Given the availability of keyhole solutions, it will often be unclear whether restrictions are necessary to address the problems that immigration raises. So, the fact that the libertarian argument for open borders gives out in extraordinary circumstances fails to undermine the claim that libertarian institutions have decisive reason to permit free movement in nearly all circumstances.

A robust justification for open borders

The above reflections suggest that libertarianism implies a robust justification for open borders. By this we mean that, if libertarianism is correct, then the reasons in favor of open borders are decisive in a wide variety of contexts. Again, we acknowledge that even libertarians can recognize that immigration restrictions are justified in rare circumstances. Nonetheless, libertarianism implies that open borders are generally morally required. Our claim in this paper is comparative: we argue that the libertarian case for open borders is far more robust than the alternatives.

We can express these claims about robustness in terms of “possible worlds.” A possible world is a complete and consistent story of the universe. The actual world is one possible way that the world could be. But there are many alternative ways that the universe could have gone, and some of them are similar to the actual world. The libertarian justification for freedom of movement is robust in the sense that, if libertarianism is true, then reasons in favor of open borders are decisive in more possible worlds than they would be if alternative theories of justice were true. As we will explain in subsequent sections, other theories of justice fail to imply that there are almost always strong moral reasons against immigration restrictions and they suggest that the reasons in favor of open borders are not decisive in some nearby possible worlds. ¹⁶

But first we might ask why we should care about producing a robust justification for open borders. Here's one reason. Many defenders of open borders see themselves as offering up a cross-cultural truth about what justice requires rather than a defense of free movement that's restricted to this particular historical juncture or cultural context (in Douglass's terms (1869), the right of free movement is “external, universal, and indestructible”). This is why advocates of open borders often claim that the right to immigrate is a human right. Recall that Kieran Oberman argues that the right to immigrate protects universal human interests and thus imposes duties on all societies to open their borders, although these duties can be overridden in extreme cases. All societies should strive to protect human rights—thus, if the right to immigrate is one such right, then all societies should aim to respect the right to immigrate. So, advocates of open borders seek to show that states have decisive reason to allow free movement in a wide variety of different contexts.

As a general rule, any human right should have what we are calling a robust justification. In further support of this thought, consider a distinction that G.A. Cohen (2003: 239–40). makes in his discussion of facts and principles. One common objection to utilitarianism is that it could require slavery if slavery would maximize utility. But Cohen distinguishes between two versions of this objection:

A: I oppose utilitarianism because if we adopt utilitarianism we might face circumstances in which (because it maximizes happiness) we should have to institute slavery, and I am against ever instituting slavery.

However, this response will fail to persuade the proponent of B. Cohen (2003: 240) remarks: “B's objection was that whether slavery is justified should not be made to ‘depend upon’ an ‘actuarial calculation.’ Saying that the result of such a calculation will always be reassuring is no reply to the objection that whether or not we institute slavery should not depend upon such a calculation.” It seems that the advocate of B wants the argument against slavery to explain why there are moral reasons against slavery that are decisive in all or nearly all circumstances. ¹⁷ People have an inviolability that should ultimately rule out slavery as a matter of principle; it's wrong to claim that slavery could be justified if it happened to maximize welfare. We can reasonably want something similar in the case of other rights as well. For example, we might prefer Judith Jarvis Thomson's (1971) defense of bodily autonomy to a utilitarian defense because it's much more robust; the utilitarian will only respect bodily autonomy when doing so maximizes social utility as a contingent matter of fact. Insofar as freedom of movement is on a moral par with other human rights required by respect for human freedom and dignity, we should prefer a theory that condemns immigration restrictions in many or most circumstances.

Utilitarianism

As in the case of the rights discussed above, utilitarianism fails to provide a robust defense of the right to immigrate. Rather, the utilitarian argument for open borders is entirely contingent on circumstances. We expect that few, if any, would deny this claim—including utilitarians themselves—so we will address it only briefly.

Some economists argue that free migration would dramatically expand the size of the world economy and produce the most welfare compared to alternative policies. According to their estimates, open borders could more than double global economic output.

How? Here's one story. In the long run, worker productivity is the major determinant of economic growth. But many workers live in places where productivity is low. They may live in countries where property rights are unprotected, for example. As a result, people in these areas are poor. But, under open borders, workers could move to high-productivity areas. They might move to countries where the rule of law is established and where property rights are protected. Workers can be much more productive in these places. So, if workers in poor countries could move to rich countries with high productivity, then their wages would go substantially up. Free migration would have other economic benefits that would boost global domestic product. The result is that open borders would sharply reduce global poverty and inequality. ¹⁸ If we ought to do whatever best promotes aggregate welfare, then perhaps states should open their borders.

The utilitarian argument for open borders is plausible enough. But the problem with the utilitarian argument for open borders is the same as the problem with almost any utilitarian argument for a specific set of legal rights and protections—it's highly contingent. If we adopt different empirical assumptions, then the argument for open borders collapses. For example, Frederic Docquier and his co-authors (2015) use a general equilibrium model to estimate the aggregate economic impact of open borders, and they find that open borders would increase the size of global gross domestic product by 11.5 to 12.5 percent in the medium term and perhaps only as little as 7 percent. While this does represent a boost for the global economy, it's considerably smaller than the estimates of other economists such as Michael Clemens.

If Docquier and his co-author's analysis is accurate, then it's simply unclear whether open borders would indeed dramatically improve human welfare, especially in light of the fact that the correlation between GDP and well-being is imperfect. And, if open borders would fail to substantially improve welfare, perhaps utilitarians should focus their attention on other policies that could deliver large gains. We are agnostic about whether Docquier et al. or Clemens is correct in this paper. But at a minimum, we can easily imagine scenarios where open borders would fail to maximize social welfare. It follows from this that the utilitarian justification for open borders is not robust.

Liberal egalitarianism

Let us now turn to what we consider libertarianism's primary competitor: liberal egalitarianism. Carens (1992) influentially argues that liberal egalitarianism justifies open borders. By “liberal egalitarianism,” Carens means a political philosophy that prioritizes both individual liberty and fair equality of opportunity. He says that liberal egalitarians want to keep inequalities as small as possible and ensure that access to social positions are not limited on the basis of arbitrary characteristics, such as race, sex, or national origin. According to Carens and other liberal egalitarians, these commitments imply freedom of international movement. For one thing, individual liberty helps justify freedom of movement. Consider the fact that domestic freedom of movement is often considered to be a human right. We have human rights to move freely within the country in which we reside. But, if respect for individual liberty requires that we have domestic freedom of movement, then individual liberty should also require freedom of international movement.

Furthermore, the value of equality also supports the case for open borders. Carens famously compares citizenship in the modern world to feudal privilege. He writes (1992: 26):

[Citizenship] is assigned at birth; for the most part it is not subject to change by the individual's will and efforts; and it has a major impact upon that person's life chances. To be born a citizen of a poor country like Bangladesh is (for most) like being born into the peasantry in the Middle Ages.

Carens then argues that equality of opportunity rules out the immigration restrictions that reinforce global inequalities. The disadvantaged need to have the freedom to move in order to access better opportunities. If people could migrate freely, this would have the effect of dramatically reducing inequality of opportunity across the world. Thus, the values of both freedom and equality support a policy of open borders.

The liberal egalitarian case for open borders is a powerful one. Nonetheless, it's considerably less robust than the libertarian justification. As discussed earlier, liberal egalitarians’ list of basic liberties is less expansive than libertarians’. Consequently, liberal egalitarians can supply a principled objection to immigration restrictions in a narrower range of cases.

Consider two of the central real-world restrictions mentioned above. First, employers are often prohibited from hiring immigrant workers. Second, property owners are often prohibited from renting space to immigrants. We’ve noted that libertarians have a ready explanation for why these restrictions are unjust—they’re incompatible with a basic right of productive private property. This right entitles business owners to hire whom they see fit and housing owners to rent to whom they see fit. The same point applies to the right of housing and airline companies to transport passengers of their choosing.

Liberal egalitarians, by contrast, do not recognize ownership of productive private property as a basic liberty. Consequently, the state is permitted to restrict a business owner's right to hire foreign workers or a property owner's right to rent to foreign tenants to promote other kinds of political values such as cultural preservation or distributive justice.

Next, consider that a prominent justification for immigration restrictions alleges that immigrants may be blocked from the domestic labor market to preserve a certain wage level for domestic workers. This justification is consistent with the commitments of liberal egalitarianism. Many liberal egalitarians accept that the state may coercively interfere with mutually agreeable economic transactions to realize a certain wage level for domestic workers, as in the case of minimum wage laws. ¹⁹ To enforce these laws, the state prohibits employers from offering, and employees from accepting, sub-minimum wage labor contracts. Such prohibitions are permissible on liberal egalitarian grounds because employers have no basic right to control their productive private property and workers have no basic right to freely enter labor contracts. On a libertarian view, by contrast, the right to own productive private property protects employers’ rights to offer sub-minimum wage labor contracts and freedom of contract protects employees’ rights to accept those contracts.

A further argument from liberal egalitarians alleges that states have duties to arrange economic institutions to preferentially benefit the domestic poor. Many have asserted that this duty is incompatible with open borders. ²⁰ For one, increased labor market competition from foreign workers is likely to be particularly harmful for low-wage domestic workers. Moreover, an influx of immigrants may strain tax-funded welfare programs, reducing their availability to the domestic poor. Some evidence also suggests that liberalized immigration policy tends to reduce domestic support for welfare programs. ²¹ Of course, whether these worries are well-founded is an empirical question, but this is precisely what robs of liberal egalitarians of a robust justification for open borders—the right to move across national borders is contingent on how the “calculus of social interests” happens to work out.

Joshi (2019: 194) suggests that libertarians are perhaps the only theorists who can reject distributive justice arguments for immigration restrictions. He explains (2019: 194):

If you think that we have special obligations to the domestic needy that justify coercion, then you should be wary of open borders proposals. Notice how radical denying such special obligations is, however. It would mean either that redistributive taxation is simply unjustified, or that rich countries should spend virtually nothing on their domestic needy, sending much of their tax collections abroad, since each dollar, euro, or yen goes much further in Bangladesh or Kenya.

As we noted earlier, libertarians argue that for positive obligations to those in need to justify coercion, the needs must be sufficiently urgent. They need not deny that people have special obligations to their compatriots; rather, they argue that, even accounting for the extra weight carried by such obligations, these obligations are typically not weighty enough to justify coercive redistribution—particularly when domestic redistribution competes with policies that target the well-being of the severe global poor. In the event of a conflict between coercive policies that benefit the comparatively rich domestic poor and those that benefit the severe global poor, libertarians will typically opt for the latter.

A liberal egalitarian might counter that open borders are required to realize global distributive justice. Recall that Carens and other liberal egalitarians contend both the values of liberty and equality justify open borders. We’ve argued that the liberal egalitarian understanding of liberty fails to provide strong support for free movement. But what about equality? At first glance, it's plausible that the value of equality of opportunity supports open borders. After all, opportunities in the world are radically unequal. People in Sierra Leone have far fewer opportunities than people in Sweden. So, it stands to reason that, to achieve equality of opportunity, states with better opportunities should open their borders to the citizens of states with worse ones.

But there are problems with this move. For one, liberal egalitarians disagree about whether equality of opportunity should extend to the whole world. Some of them argue that only the citizens of a common state have claims to equal opportunities. ²² Even if these statist egalitarians are wrong and everyone in the world has entitlements to equality of opportunity, open borders still wouldn't follow because it's possible for people in different countries to have equally valuable opportunities without open borders. For instance, a Canadian and an American can have an equal opportunity to work as a well-paid mechanic even if they are not permitted to pursue this sort of job in the other's country. ²³

Moreover, a global equality of opportunity principle wouldn't arbitrate in favor of open borders against (effective) global redistribution. Suppose that Americans have economic opportunities that are not equal to those of Canadians. This inequality can be rectified without opening the border between the United States and Canada. Canada could instead transfer resources to the United States to ensure that American opportunities are comparable to Canadian opportunities. In sum, it is, at a minimum, possible for citizens of different countries to satisfy a principle of equal opportunity without open borders and such a principle is probably even satisfied in certain real-world cases.

Let's set aside economic issues to consider how liberal egalitarians can respond to cultural arguments for immigration restriction. Joshi argues that defenses of open borders set the bar for permissible coercion implausibly high. For instance, it seems permissible for the state to coercively enforce regulations of, and contributions to, national parks. ²⁴ Joshi argues that this is because the state may employ coercion to supply intrinsically valuable goods; one might repurpose his argument to claim that the state may employ coercion to preserve and promote particular sorts of cultural and social values. After all, states coercively enforce regulations of, and contributions to, not only national parks, but also art museums, public radio, public television, and more.

These policies are consistent with most forms of liberal egalitarianism. Rawls (2005: 214), for instance, argues that the standards for publicly justifying state coercion are relaxed with respect to policy issues that don't concern “fundamental matters,” including “establishing national parks and preserving wilderness areas and animal and plant species; and laying aside funds for museums and the arts.” Moreover, recall Stilz's worry (2019: 204) that the libertarian view of freedom that motivates some defenses of open borders would show “environmental or historic preservation laws” to be illegitimate. Liberal egalitarians also tend not to object to a system of coercively funded and regulated public schools that, among other things, teach the English language and narratives about American history that inculcate certain cultural values in students.

Liberal egalitarians argue that basic liberties may not be compromised for the sake of cultural preservation; however, the number and scope of such liberties are sufficiently limited so as to render liberal egalitarianism compatible with state coercion exercised for the sake of cultural preservation. To take two specific examples, liberal egalitarians recognize only limited basic rights of association and personal property. There is little doubt that citizens can develop and exercise their moral powers while being restricted in their right to associate with at least some foreign collaborators, coreligionists, and family members who may disrupt the domestic culture. (Indeed, Rawls himself seems committed to the claim that citizens can adequately develop and fully exercise their moral powers without associating with foreigners given that his account of a fully just society assumes a closed nation state). Citizens can also develop and exercise their moral powers despite being compelled to allocate some of their income in support of tax-funded museums and media—thus, liberal egalitarians should have no in-principle objection to authorizing the state to employ its coercive power to promote and preserve specific cultural values.

There are other arguments for the claim that immigration restrictions are unjust that we lack the space to consider; here we will simply note that they tend to appeal to contingent features of real-world immigration policies and thus fail to supply a robust defense of open borders. ²⁵

Objections

At this stage, you might object that the libertarian case for open borders is not as robust as it first appears. For instance, a libertarian state may restrict immigration at the will of the private property owners that reside within its territory. ²⁶ Just as property owners may pool their entitlements in a gated community that restricts outsiders’ access, they may do the same on a national scale.

As an initial response, it's worth clarifying a conceptual point. Libertarian institutions enforce the right of private property owners to exclude others from the use of their property. However, as Carens notes (1987: 253–4), Nozickean libertarianism

provides no basis for the state to exclude aliens and no basis for individuals to exclude aliens that could not be used to exclude citizens as well. Poor aliens could not afford to live in affluent suburbs (except in the servants’ quarters), but that would be true of poor citizens too. Individual property owners could refuse to hire aliens, to rent them houses, to sell them food, and so on, but in a Nozickean world they could do the same things to their fellow citizens. In other words, individuals may do what they like with their own personal property. They may normally exclude whomever they want from land they own. But they have this right to exclude as individuals, not as members of a collective. They cannot prevent other individuals from acting differently (hiring aliens, renting them houses, etc.).

There is a significant moral difference between the state directly mandating exclusion and the state enforcing a right that results in exclusion as a side effect. If the state enforces a homeowner's right to stop a doomsday prophet from preaching in their kitchen, they haven't violated the prophet's freedom of religious practice. By contrast, the prophet's freedom would be violated if the state enforced a law forbidding the prophet from building and peacefully worshipping in a temple of her own design. Thus, there is a meaningful difference between states that mandate a form of coercive exclusion and individuals that exercise their rights in ways that result in exclusion.

Perhaps you’ll grant the conceptual point, but argue that it's a distinction without a practical difference. In the world where all property owners exclude foreigners, foreigners can't enter the country and work and reside here. That's ultimately what matters.

In reply, we’ll first reiterate an earlier point: no plausible theory will justify open borders in all possible worlds. The question here is comparative: how likely are extensive immigration restrictions under libertarian institutions relative to the alternatives? As a comparison, consider again liberal egalitarianism. We have already argued that liberal egalitarianism implies significant immigration restrictions in many possible worlds. (And some liberal egalitarians themselves believe that immigration restrictions are justified in the actual world.) By contrast, the pooling of entitlements scenario is one realized only in a remote possible world with an extraordinary distribution of preferences.

Furthermore, even in a world in which most property owners wished to exclude foreigners, such restrictions would be unstable for the reasons suggested by economist Becker (1957). Property owners who refuse to buy from, sell to, or hire foreigners would be at a competitive disadvantage compared to those who do not refuse. For instance, anti-immigrant employers incur higher expenses to obtain the same productivity. Nondiscriminating employers can increase profits by hiring cheaper immigrant labor. Over time, then, nondiscriminating employers will outcompete and displace discriminatory employers. ²⁷

Indeed, evidence indicates that capitalists lobby for fewer immigration restrictions precisely for the sake of access to cheaper labor. ²⁸ Interestingly, this practice has been acknowledged and lamented by opponents of capitalism. For instance, Marx (1867) writes, “A study of the struggle waged by the English working class reveals that, in order to oppose their workers, the employers either bring in workers from abroad or else transfer manufacture to countries where there is a cheap labour force.” In a similar vein, Lenin (1913) writes: “Capitalism has given rise to a special form of migration of nations. […] There can be no doubt that dire poverty alone compels people to abandon their native land, and that the capitalists exploit the immigrant workers in the most shameless manner.” Even Rawls and Van Parijs (2003) came to view free movement as a part of a political agenda pushed largely by capitalists. Thus, capitalism's critics should, by their own lights, doubt that domestic capitalists would collaborate to exclude foreign workers from the labor market.

Of course, none of the above rules out the possibility of a society in which all employers and customers are so committed to anti-immigrant discrimination that they’re willing to absorb significant material costs to exclude immigrants. But a society with this distribution of preferences will not allow open borders under non-libertarian institutions either. Consider an egalitarian alternative of collective ownership of productive property. Let's suppose domestic workers vote on whether to permit foreigners to work in their democratically-controlled cooperative. Presumably, they’ll all vote for exclusion because of their anti-immigrant prejudice. Indeed, if anything, a regime of democratically-controlled productive property creates stronger incentives to indulge anti-immigrant prejudice. ²⁹ A worker who casts a non-decisive vote to exclude immigrants from their workplace suffers little material cost for doing so. By contrast, an employer who refuses to hire cheaper but equally productive labor may lose their business as a result. Under the conditions assumed by the objection, then, it's hard to see how alternative institutional structures will result in open borders. Thus, this objection doesn't establish any robustness advantage of non-libertarian institutions.

Some implications

This completes our argument for the conclusion that libertarianism supplies a uniquely robust justification of open borders. A key question remains: does this result vindicate libertarianism or should it weaken the case for open borders?

With our conclusion in hand, you could make the following argument. Libertarianism provides a comparatively robust justification of open borders—if libertarianism is true, then the reasons in favor of open borders are decisive in a wide variety of contexts and nearby possible worlds. In contrast, other defenses of free movement, such as utilitarian and egalitarian arguments, fail to provide a similarly robust defense of open borders. These arguments for free movement are more sensitive to contingent circumstances in comparison with the libertarian one.

Next, let's suppose that, like most political philosophers, you’re inclined to reject libertarianism. You should thus conclude that open borders lack a robust justification. In other words, if you reject libertarianism and only libertarianism offers a robust justification for open borders, then the case for open borders is weaker and more contingent than you might have thought.

In this way, our argument shows why critics of libertarianism should have reservations about open borders. To illustrate, consider prominent political theorists and philosophers who reject open borders, such as Walzer (1984, chapter 2) and Miller (2016). Walzer (1984) and Miller (1990) criticize libertarian views about economic justice and they emphasize the importance of economic equality and social democracy. Moreover, Walzer and Miller both argue in favor of communitarianism and nationalism about global justice and defend the importance of shared membership for our obligations to one another. Libertarians generally oppose these positions. Libertarians favor freedom of contract and robust rights of private property, and they tend to endorse cosmopolitan views about global justice. ³⁰ So, our argument can explain why political theorists like Miller and Walzer who disagree with libertarians on other issues, such as economic justice and the importance of national identity, also have good reasons to be skeptical about free international movement. If a robust case for open borders rests on libertarian premises, then philosophers who reject libertarianism should similarly be less inclined to endorse open borders.

On the other hand, our argument can indirectly support libertarianism. As we’ve observed, a growing number of philosophers accept that the right to immigrate is a human right. These philosophers may be inclined to agree that there's a robust argument for open borders. And let's assume that our central argument in this paper succeeds: only libertarian principles can provide this kind of justification for open borders. So, philosophers who agree that people have human rights to immigrate have a reason to favor libertarian principles. We doubt that many people who were inclined to be skeptical of libertarianism will be entirely persuaded by this argument for libertarianism. Nonetheless, our argument gives people who are sympathetic to open borders a reason to be more sympathetic to libertarian principles. Philosophers who defend open borders should positively update their credence in the plausibility of libertarian principles.

Consequently, our arguments might prompt a fresh assessment of libertarian principles by casting them in a new light. Take freedom of contract. It is plausible that foreigners are within their rights to accept a job in their destination country that pays wages higher than those available in their home country even if those wages fall below what their destination country deems a permissible minimum. It is true that, in a meaningful sense, their new employer exploits their economic vulnerability. Still, blocking an immigrant from an employment opportunity that pays more than their best available alternative does them little good and denies them the right to live their lives in accordance with their own plans and values. But notice that this thought lends support for a stronger conception of freedom of contract than liberal egalitarians typically endorse. It would, for instance, imply the impermissibility of minimum wage laws that prohibit employees from agreeing to labor contracts that pay them a sub-minimum wage.

Consider also the urgency of need that is required to merit the state's exercise of its coercive power. Here again, it is plausible that coercive interference with someone's liberty to dispose of their personal property is not warranted to fund art museums primarily patronized by the wealthy or to enrich a compatriot in the top 10% of world earners at the expense of enriching a foreigner living on less than two dollars per day.

Lastly, our argument bears on recent debates over whether egalitarian forms of liberalism have conceded too much ground to values other than liberty. ³¹ In A Theory of Justice, Rawls (1999: 220) defended “the most extensive total system of equal basic liberties compatible with a similar system of liberty for all” and argued (1999: 179) that “…a basic liberty…can be limited only for the sake of liberty itself.” However, these basic rights have come to be understood as only guaranteeing citizens’ adequate liberty. Yet one might object that the liberal state should prioritize the protection of even non-essential exercises of freedom. A religious practitioner may well be able to adequately develop their conception of the good and sense of justice while being prohibited from inviting an additional coreligionist to join their congregation; still, it's sensible to think they are within their rights to do so.

To be sure, the preceding claims remain controversial. Perhaps they should be rejected. However, we think that appreciating their relevance to the case for a robust freedom to immigrate reveals them to be more plausible than commonly believed.