If any specter is most clearly haunting the wealthiest states of the world today, it is the specter of nativism. It has become a tired cliché to recount the number and nature of political forces that have risen on the strength of fear of the migrant other, real or imagined. What is less thoroughly documented is the extent to which those forces span class and ideological divides. It is not merely the populist Trumps, Farages, Orbáns, and Salvinis who call for migration moratoria, nor characteristically compromising centrists of all stripes, but any number of leftists who have voiced opinions characterizing newcomers either as “culture war” wedge issues in otherwise straightforwardly politico-economic fights or cheap labor scabs imported to keep the incomes of the working class under water.
Bernie Sanders’ record on the issue is symptomatic of the tendency: denouncing guest-worker programs proposed in US immigration legislation as wage-lowering , excoriating the very idea of “open borders” as a “Koch brothers proposal” , and most recently declining for a time to call for the shutdown of the notorious Immigration and Customs Enforcement (ICE) agency , the most vicious instrument of Trumpist border fetishism. Across the pond, Jeremy Corbyn speaks sympathetically about refugees, but has also claimed that “wholesale importation of underpaid workers from central Europe” as a consequence of the free movement mandated by EU membership “destroy[ed]” conditions of labor for British workers, a position that partly explains his refusal to oppose Britain leaving the bloc–or to offer a lifeline to those “EU migrants” already in Britain who face expulsion.  At the same time, left intellectuals like Slavoj Žižek and Perry Anderson write, respectively, of refugees as disruptors of a European dialogue on class struggle  and of labor migrants as deregulated “factors of production”–as if they were merely machine tool parts slotted into transnational supply chains whose purpose is to lower expenses and whose effect is to replace class politics with anti-immigrant Kulturkampf.  Meanwhile, alliances of left thinkers like Wolfgang Streeck and politicians like the German Left Party’s Sahra Wagenknecht have promoted an anti-immigrant politics that supposedly engenders a securely “generous” pro-welfare population–to such a degree, in fact, that such politics have been compared to explicitly “national social” programs mooted on the far right. 
Yet these are far from the only voices on the left speaking out on migration. Sanders declining to call for an end to ICE angered his base to the point that he was forced to walk back his stance. Large numbers of Labour voters believe that Brexit is a cynical Tory austerity trap. And socialist politicians all along Europe’s Mediterranean coastal “front line”–where migrant arrivals on the continent are felt most acutely–seem to be the least likely to support craven agreements of highly questionable legality with Middle Eastern and North African states to detain or repulse hopeful asylum-seekers. Indeed, where there is any hope today for a world more open to the free movement of human beings, it arises most often from the left side of the proverbial political aisle.
What the immigration advocates of the left lack, however, is a clear and convincing theory for skeptical members of their coalition in the working class–a class whose potentially right-“populist” votes are often cited as apologies for Corbyn’s and Wagenknecht’s positions. And the language of rights is clearly an insufficient one in this context. Even the most emotive claims to the human right to asylum (undergirded by humanitarian sympathy), the right to free movement (supported by appeals to liberty), or simply the right to equal treatment pale in comparison to more visceral cultural and–more importantly for the left–economic anxieties. After all, such anxieties can also be expressed in terms of rights: to national self-determination, for example, or social rights perceived as tied to finite resources. It may be salutary to wonder, given this practical incompatibility of left ideals and the impasse between left factions, what that grandfather of so much leftist political and economic theory, Karl Marx, had to say on the subject.
Marx’s views on migration are few and far between. His clearest sentiments are contained in an 1870 letter to his New York associates Siegfried Meyer and August Vogt.  Like so many of Marx’s observations on the subject, they concern Ireland. In this case, Marx’s subject is Irish immigrants in England, driven off their land by processes of enclosure undertaken by the English aristocracy on their home island. Interestingly, Marx does not concern himself so much with the actual question of whether the Irish newcomers drive down English wages, but with how this notion was taken up discursively by English workers. “Every industrial and commercial center in England now possesses a working class divided into two hostile camps”, he writes:
The ordinary English worker hates the Irish worker as a competitor who lowers his standard of life. In relation to the Irish worker he regards himself as a member of the ruling nation and consequently he becomes a tool of the English aristocrats and capitalists against Ireland, thus strengthening their domination over himself. He cherishes religious, social, and national prejudices against the Irish worker. … This antagonism is the secret of the impotence of the English working class, despite its organization. It is the secret by which the capitalist class maintains its power. 
Marx’s thinking on migration thus appears, at first glance, to have much in common with the school of thinking that cultural difference undermines working-class solidarity, and with it the ability to advance left causes politically–though with the important caveat that he views this antagonism as consciously stoked by capitalists through the press, perhaps suggesting that it is some superstructural distraction rather than something inherent in a working class facing a cultural divide.
But, of course, it is not for Marx to shy away from the underlying politico-economic question of wage competition. Many of his thoughts on the subject are embedded in the larger theory of “primitive accumulation”–the violent property seizures that first make the process of continual capital accumulation possible –that he sets out in volume one of his nearly contemporaneous Capital. Marx’s analysis of this phenomenon also focuses on the process of enclosure, which he views as pushing those driven off rural land by estate formation to cities–in other words, producing rural-urban migration of the sort that could occur both in relatively close proximity (from, in his chief example, the Scottish Highlands to cities like Glasgow) or across borders and seas (from, for instance, Ireland to English industrial centers). For Marx, migration was partly (though certainly not entirely) a consequence of weak or unenforceable rights to the land on which one labored–a rebuke to the Lockean theory of property in which labor conferred rights (and dignity). The rural migrants who are thereby dispossessed thus constitute what Marx calls the “reserve army of labor”, whose demand for work in industrial cities can overwhelm supply and drive competition to toil for lower wages. This suggests a Marx who believes that migration undermines working-class fortunes materially, in addition to having the potential to feed into working-class disunity.
Yet the “reserve army” thesis focuses on conditions of labor in industrial centers, not in the rural districts where the number of laborers have fallen. This led some of Marx’s critics to argue that urban migration has the effect of improving the bargaining position of laborers in rural areas. The “reserve army” theory also depends upon migration occurring within a closed system. In truth, many turned-out tenant farmers in the British Isles took the option–in lieu of remaining on or near the land or joining the “reserve army of labor”–of overseas emigration. In the far-flung settler colonies, members of Britain’s “surplus population” could visit on native populations the same dispossession that the process of primitive accumulation had visited on them, themselves becoming (at least in theory) unencumbered property owners. Moreover, the reduction of the overall surplus through emigration could even reduce the numbers of the “reserve army”, improving conditions of labor for all.
“Like the world in general, we are assured”, Marx summarized this position in one of his articles for the New York Daily Tribune, “that Ireland in particular is becoming a paradise for the laborer, in consequence of famine and exodus”.  He planned to take on the argument that emigration could produce better bargaining conditions for remaining labor in an undelivered speech on Ireland written the same year as the appearance of volume one of Capital.  Despite acknowledging that emigration had left wages high, his notes for this unread speech observed that the overall condition of those remaining in Ireland had not improved. Much of the problem was that there was now insufficient labor remaining in rural Ireland. The newly consolidated farms could not be run efficiently. Combined with the increased rent demands of landlords, this left the population suffering a greater degree of exploitation and enjoying less of the land’s produce.
What Marx demonstrated, in other words, was that there were conditions in which the opposite of a “reserve army of labor”–the lack of a sufficient workforce–could also produce depredations equal to or worse than those he had blamed on the oversupply of working bodies. Perhaps the most obvious contemporary analogy is the ongoing “brain drain” from countries of emigration in the global South. But like the famine that ravaged Ireland and fostered much of the emigration that Marx addressed, the problem of low birthrates in today’s advanced capitalist countries will also increasingly undermine their economic efficacy, heaping ever increasing labor loads on the remaining workforce.
“We suffer not only from the living”, Marx wrote in the introduction to the first German edition of Capital, “but from the dead”.  He was concerned there with the survival of “antiquated modes of production” in changing economies, like those farmers struggling to adapt to enclosure in Ireland, but he may as well have been speaking about the problems facing aging industrial societies today, with their shrinking labor forces and tottering pension schemes. His unread speech is a window on how under-population may empower capitalist exploitation as surely as overpopulation can. Various advanced capitalist states have attempted natalist approaches or even automation to counter the impact of under-population on the availability of labor, but the one proven recourse remains immigration. If there is a risk that it produces a “reserve army of labor”, there is also a risk that the lack thereof produces its own economic calumny, one about which the left should perhaps be no less concerned. Thus far this issue has been highlighted only in the dry, technocratic tones of Economist editorials. Marx’s analysis could illuminate it as a license for equally cruel and extractive labor, threatening the abundant economic circumstances that are the basis for the very social rights nativists howl migration might take away.
All this might seem like a roundabout way to arrive at a Marxist case for immigration. Yet more “direct” theoretical approaches–one can imagine an argument to end the alienation of peripheral workforces from the wealth produced in the global core–may also be more abstract, and less fruitfully mobilizing. And while tackling the question of migration as one of nationalism–a subject on which Marx wrote more frequently–might avoid that problem , it does not offer a more obvious path to engaging with the materialist concerns that underpin potential working-class hostility to migration.
One might also think that it would have made more sense to begin instead with Marx’s own life story. The man was, after all, a refugee in not one but a variety of countries (the “police spies” who make an appearance early in the Communist Manifesto were the ICE of their day); his closest associate, Engels, spent much of his life in a relationship with an Irish immigrant to England; both were inveterate promoters of an internationalist labor movement and sought to overcome national boundaries in favor of class unity. But refugee status in Marx’s time was given to individual political apostates; it was not burdened with the concerns over mass influx our politics face. Nor did his internationalism often extend much beyond Europe; he viewed India, in at least some of his writing, as subsisting at some lower stadial rung of social development that might only be overcome through colonialism, unpalatable as that was.  Without becoming inexcusably ahistorical, it is difficult to see any of these biographical details easily applying to migration as it preoccupies most of present-day “developed world” politics.
Even if his observations on India might suggest Marx would side with those who would promote development to stymie migration, this understanding does not exactly comport with his last word on Ireland. If race occasionally blinded him to it elsewhere, he could see that the island’s economic condition was a recent setback rather than a primordial or natural handicap–and did not require outside assistance so much as revolutionary reversal. Only this would end the difficulties he saw stemming from immigration in England. As he wrote to Meyer and Vogt, “the national emancipation of Ireland” was “the first condition of … [the] social emancipation” of the English working class.  Only then would Ireland be unshackled from the system that led it to produce the “reserve army” that could be made to seem their enemy. (He might have–but did not–reflect further upon how this intertwining of fate–a necessarily revolutionary Irish migrant community living among the English working class–could build the kind of cross-border solidarity he sought among stationary workers elsewhere. Marx was always a better student of the dialectical certainties of Hegel than the cosmopolitan potentialities of Kant.) Marx extended the same theory of primitive accumulation to the colonial plunder of the non-European world that he had to the enclosure of Ireland, and it stands to reason that a Marxist approach to migration today might advance the same revolutionary remedy for the postcolonial territories that currently serve as the springboard for so much human movement toward the global North.
But what would that remedy look like? If, for Marx, unequal property rights are a root cause of migration, then its revolutionary opposite might reasonably be inferred to involve either the redistribution of property or its outright abolition. Whether states currently producing large numbers of migrants would be willing to walk this path–one many have now been down before–seems much less likely now than Irish emancipation did at the end of the nineteenth century. And it seems just as unlikely, especially given the impact of political instability on migration, to put to rest the specter of nativism in advanced capitalist countries. Perhaps emphasizing Marx’s warnings about under-population would not either. But at least it might change the conversation productively, while proffering increased freedom of movement as an answer to exploitation, rather than the root of it. As Marx always recognized–and in which he was proven correct by the insufficiency of the eventual Irish revolution for improving the state of the English working class–migration was, if anything, only ever at most a part (“the first condition”) of those workers’ problems, and the reaction to it more a symptom of larger issues than it was that reaction’s cause. So it remains.
 Seung Min Kim, “Sanders and Immigration? It’s Complicated”, Politico (19 June 2015), available at https://www.politico.com/story/2015/06/bernie-sanders-and-immigration-its-complicated-119190.
 Ezra Klein, “Bernie Sanders: The Vox Conversation”, Vox (28 July 2015), available at https://www.vox.com/2015/7/28/9014491/bernie-sanders-vox-conversation.
 “Sanders Declines to Call for Abolishing ICE”, CNN (24 June 2018), available at https://www.cnn.com/videos/politics/2018/06/24/sotu-sanders-ice.cnn.
 Helen Lewis, “Jeremy Corbyn: ‘Wholesale’ EU Immigration Has Destroyed Conditions for British Workers”, New Statesman (23 July 2017), available at https://www.newstatesman.com/politics/staggers/2017/07/jeremy-corbyn-wholesale-eu-immigration-has-destroyed-conditions-british.
 Slavoj Žižek, “In the Wake of Paris Attacks the Left Must Embrace Its Radical Western Roots”, In These Times (16 November 2015), available at http://inthesetimes.com/article/18605/breaking-the-taboos-in-the-wake-of-paris-attacks-the-left-must-embrace-its.
 Perry Anderson, “Why the System Will Still Win”, Le Monde diplomatique (March 2017), available at https://mondediplo.com/2017/03/02brexit.
 Philip Oltermann, “Germany’s Left and Right Vie to Turn Politics Upside Down”, The Guardian (22 July 2018), available at https://www.theguardian.com/world/2018/jul/22/german-leftwingers-woo-voters-with-national-social-stance.
 Karl Marx to Siegfried Meyer and August Vogt [9 April 1870], in Karl Marx and Frederick Engels, Selected Correspondence (Moscow: Progress Publishers, 1975) 220; also available at https://www.marxists.org/archive/marx/works/1870/letters/70_04_09.htm.
 Ibid (original emphases).
 Karl Marx, “On the Labor Contract”, New York Daily Tribune (29 July 1853), available at https://www.marxists.org/archive/marx/works/1853/07/29.htm.
 Karl Marx, “Notes for an Undelivered Speech on Ireland” [26 November 1867], in Karl Marx and Friedrich Engels, Marx and Engels on Ireland (Moscow: Progress Publishers, 1971) 120; also available at https://www.marxists.org/archive/marx/iwma/documents/1867/irish-speech-notes.htm.
 Karl Marx, Capital: A Critique of Political Economy, vol. 1 (Harmondsworth: Penguin, 1976 ), 91; also available (in different translation) at https://www.marxists.org/archive/marx/works/1867-c1/p1.htm.
 As Erica Benner’s work has shown, Marx’s materialism was no less robust in tackling the “idealism” of mid-nineteenth-century nationalists. See Erica Benner, Really Existing Nationalisms: A Post-Communist View from Marx and Engels (Oxford: Oxford University Press, 1995).
 See especially Karl Marx, “The British Rule in India”, New York Daily Tribune (25 June 1853), available at https://www.marxists.org/archive/marx/works/1853/06/25.htm.
 Marx to Meyer and Vogt (original emphases).
Chris Szabla is a PhD candidate in history at Cornell University and most recently Lecturer in International Law at Cornell Law School.