This past spring, the far-right nativist quarterly The Social Contract dedicated an issue to the legacy of the late Garrett Hardin, the controversial ecologist and writer best known for his essay “The Tragedy of the Commons,” published in Science in 1968. Alongside reprints of an old interview with Hardin and new appreciations from figures like former Colorado governor Richard D. Lamm ran more standard fare from the journal, including articles headlined “The Madness of Illegal Alien Violence” and “Open-Borders ‘Journalist’ Attacks Warren Buffett.”

The Social Contract has occupied a fringe outpost in the conservative movement for all its history. Edited by a racist who was also a member of a dead-ender segregationist group, the journal has long inveighed against “invaders,” migrant crime, and multiculturalism. While publishing influential intellectuals of a paleoconservative bent, they have also run cruder rants darkly warning of the eclipse of Western Civilization by a rising tide of color. So it’s significant just how quickly many of the ideas articulated in The Social Contract, or developed into policy and advocated for by anti-immigrant groups in its close orbit, now find expression in the highest reaches of the U.S. government under the Trump administration. Missing from this spectacular achievement of the nativist right, however, is one front in the anti-immigrant fight embodied by Hardin: environmental conservation.

As the climate crisis worsens, denialism itself might very well go extinct, opening up the possibility of new political configurations in response to the question of what to do about it.

For decades, Hardin was a titan of the nativist movement and a close collaborator of John Tanton, an ardent conservationist and founder of a network of hardline anti-immigrant institutions including The Social Contract, which reprinted “The Tragedy of the Commons” in its inaugural issue. It was in a letter to Hardin that Tanton rather infamously wrote, “I’ve come to the point of view that for European-American society and culture to persist requires a European-American majority, and a clear one at that.” Both Tanton and the editor of The Social Contract press served as founders of The Garrett Hardin Society, an online archive of Hardin’s writings and interviews. What Hardin brought to the nativist movement was his cachet as a famous ecologist, which he used to push a neo-Malthusian logic in arguing against immigration. The specter of out-of-control population growth in developing countries, enabled by naive UN food programs, was leading the planet to ruin, Hardin argued. And allowing poor immigrants into wealthier countries created the conditions for yet more population growth, pushing the “carrying capacity” of nations past their limit. This “green” appeal against immigration was tremendously seductive to the mainstream environmental movement of the 1970s, the era of “The Population Bomb,” and was only jettisoned in the late 1990s and 2000s, much to the enduring bitterness of nativists who believed they had common cause.

The Social Contract’s recent celebration of Hardin came at a dark time. On March 15, a white supremacist in Christchurch, New Zealand, murdered fifty-one worshippers at a mosque. In a sprawling manifesto, the killer identified as an “ecofascist” and aimed to “show the invaders that our lands will never be their lands.” Less than six months later, another man who combined resentments about environmental degradation and immigrant populations in his manifesto walked into a Walmart in El Paso, Texas, with a rifle and killed twenty-two people, many of whom were Latinx. “Invaders” the killer wrote, “have close to the highest birthrate of all ethnicities in America.”

Climate denialism remains deeply entrenched on the American right, but the glaciers are beginning to recede; recent polls show increasing alarm about the climate crisis across the political spectrum, especially among the young. As the crisis worsens, denialism itself might very well go extinct, opening up the possibility of new political configurations in response to the question of what to do about it. This is already underway in many European countries, where younger activists within far-right parties—those who will have to live with the worsening effects of climate change—are agitating to cut into green parties’ monopoly of the issue by tying it to their anti-migrant appeals.

Fifty years after it was written, Hardin’s “Tragedy”—the parable of a shared pasture inexorably overrun by individual herders’ self-interest—remains extensively anthologized, cited, and taught. According to the Open Syllabus Project, it was one of the most-assigned essays in university syllabi in the past ten years. It can be found on YouTube, where TED-Ed and Khan Academy have short animated videos on the topic for the curious student. I first encountered the article during my senior year of high school at an alternative public school focused on environmental science. Hardin, along with the writings of Paul Ehrlich, were assigned during a winter unit dedicated to understanding the effects of human population on the environment. To this day, I still feel the moral pull of having no more than two children; when I reflect back on how I arrived at this belief, it is intertwined with memories of my school’s front doors, its cafeteria.

Certainly, the study of the human population’s impact on the environment is not inherently racist. But the question remains why one of the most widely disseminated articles on the topic comes from a thinker so compromised by racism. And the essay’s status as conventional wisdom suggests that the environmental logic that marked Hardin’s work could easily find its way into mainstream politics again.

Hardin espoused eugenicist beliefs from the start, long before “The Tragedy of the Commons” achieved its exalted status. Early in his career, four years after the end of World War II, he published a college textbook, Biology: Its Human Implications. Mostly, it covered the basics of biology, but in the final chapter, titled “Man: Evolution in the Future,” Hardin provided undergraduates with a full discussion of positive and negative eugenics, making the case in support of both in order to prevent a dysgenic future. He writes:

In all cases, the studies indicate that as long as our present social organization continues, there will be a slow but continuous downward trend in the average intelligence . . . The sterilization of the feeble-minded has been opposed for various reasons. One of the strongest reasons has been the feeling that it somehow interferes with the “rights” of the individual. In discussing this point, one must first emphasize that sterilization alters an individual in one respect only: it keeps him from having children.

This ideological commitment was to last a lifetime. Decades later, Hardin’s 1993 book, Living Within Limits, thanked the pro-eugenics funder the Pioneer Fund. Hardin collaborated with the racist academic Virginia Abernethy, who later described herself as an ethnic separatist and was the vice presidential candidate on the ticket of an obscure white nationalist political party in 2012. Seven years before his death, Hardin was invited to a eugenics conference along with several other prominent scientific racists, including J. Philippe Rushton, Arthur Jensen, and Richard Lynn, where the group founded an organization called the Society for the Advancement of Genetic Education. As reported by another proud eugenicist who attended the meeting, “the organization was still-born because the newly-elected president soon realized that if he got involved with eugenics, his anti-immigration work would suffer.” That president was John Tanton.

More insidious than his many private connections to the eugenics movement, however, was Hardin’s success in popularizing biological concepts in service of eugenic arguments. In 1960 he wrote about the competitive exclusion principle in Science, an essay later included in his collection Stalking The Wild Taboo. The principle holds that in a resource-finite environment, two different populations fighting over the same resources cannot stably coexist; one will win out over the other. Like the commons, these abstract but commonsense sounding ideas were presented as immovable laws of nature. (In the essay, Hardin argues that the competitive exclusion principle cannot be “subject to proof or disproof by facts, ordinarily understood.”)

Fast-forward thirty years, and it’s easy to see why the concept was important to him. In effect, Hardin was implying that the competitive exclusion principle as applied to a country like the United Kingdom or the United States suggests that unchecked immigration could lead to (presumably white) genocide:

If two cultures compete for the same bit of turf (environment), and if one of the populations increases faster than the other, then year by year the population that is reproducing faster will increasingly outnumber the slower one. If, “other things being equal,” there are advantages to being numerous, then in time the slowly reproducing population will be displaced by the fast one. This is passive genocide. It may be that no one is ever killed, but the genes of one group replace the genes of the other. That’s genocide.

Equally revealing are how Hardin’s ideas have been expressed by those who share his political convictions. A writer for the white nationalist publication Occidental Observer cited Hardin last year when writing that “the roots of the political principle of apartheid are found in biology and ecology.” “The logic of apartheid is implicit in the competitive exclusion principle,” she continued, in a defense of the South African apartheid regime, which stands as one of the most important case studies for modern white supremacists thinking about white political control.

More insidious than his many private connections to the eugenics movement, however, was Hardin’s success in popularizing biological concepts in service of eugenic arguments.

Hardin’s 1974 essay “Lifeboat Ethics” also remains influential on the far right. In an anthology assembled by Hardin and titled Managing the Commons, a footnote to the essay, published under the title “Living on a Lifeboat,” complains that the original title was simply “Lifeboat Ethics,” and that an editor at Psychology Today added the “inflammatory” subtitle “The Case Against Helping the Poor.” Hardin was consistent in his focus on the threat of the world’s wretched poor, however, and keepers of Hardin’s legacy have emphasized the importance of this thread. His metaphor—that the finite planet is a lifeboat with a limited carrying capacity which necessitates making hard choices about the poor souls out in the water—has found direct expression in the European migrant crisis, where flotillas of refugees continue to cross the Mediterranean seeking asylum, many drowning in the attempt.

In the midst of it, a white supremacist writer referenced the essay in an article for VDare, writing that “Hardin’s prescriptions for averting the Malthusian catastrophe—they included eugenics, an end to welfare and foreign aid, and allowing famines to take their course—were too strong for most people.” Another article invoking Hardin on stopping the “refugee invasion” by a Canadian nativist writer was reprinted on the neo-Nazi website The Daily Stormer which now features a demographic countdown clock on its sidebar. The Finnish ecofascist Pentti Linkola once put a finer point on Hardin’s metaphor, writing: “What to do, when a ship carrying a hundred passengers suddenly capsizes and there is only one lifeboat? When the lifeboat is full, those who hate life will try to load it with more people and sink the lot. Those who love and respect life will take the ship’s axe and sever the extra hands that cling to the sides.”

Where Hardin’s legacy is most embraced today, if not explicitly referenced, is at the border. In a 1997 letter to the ACLU denouncing the civil rights organization for defending the Fourteenth Amendment’s citizenship clause, Hardin wrote about being “daily confronted with hordes of highly pregnant Mexicans coming across the border at the last minute and having their babies in American hospitals—at American expense,” anticipating the rise to prominence of the nativist “anchor baby” talking point by nearly a decade, and the El Paso massacre by two.

Late last year, an English writer for the white nationalist website Counter-Currents wrote a book review titled “Environmentalism and White Nationalism: A Shared Destiny,” arguing that

environmentalists and “White Nationalists” . . . are cogent and persuasive in perceiving a major problem in the world, but inadequate and unconvincing in offering ways to meet the challenges they describe, because each is blind in one eye. Environmentalists react allergically . . . to anything which smacks of racial differentiation (“racism”), whilst those who are racially conscious strike what is usually no more than an insincere pose—one without substance or seriousness—on the subject of the environment. . . . Environmental degradation and population explosion constitute the two sides of one and the same challenge and disaster. It is time to connect the dots.

Watching Tucker Carlson on any given night, or the president for that matter, and it’s obvious just how deeply white nationalist ideas have penetrated the mainstream. That’s why it’s essential that the left and environmentalists can’t get too comfortable with their current dominance on the issue of fighting the climate crisis. Writers like Betsy Hartmann have written perceptively about how alarmist concern over potential climate migrants could ultimately play into the hands of both ethnonationalist movements and the national security state. American white nationalists have already begun to spread “plant more trees; save the seas; deport refugees” propaganda.

And Senator Bernie Sanders’s recent stumble at CNN’s Climate Town Hall on a question about population and abortion rights—posed by an audience member who called the topic “poisonous for politicians, but . . . crucial to face”—underscores that it’s more than just “Science Is Real” liberals who are susceptible to deceptive, Hardin-esque “common sense” on the topic of population. Carbon intensive industries, and not poor populations, are the primary culprit of the climate crisis. Irrespective of climate change, all women should have access to contraceptives and safe abortion services.

Hardin was not wrong in his insistence on the limits of economic growth, but his preferred interventions are of a different sort entirely; they are authoritarian, and they are ethnonationalist.

It’s worth noting that the only criticism Sanders received for accepting the premise that the planet is facing an overpopulation problem was from the anti-abortion right, a bloc that long saw the Hardin and Tanton network for what it really was. But in imagining a future where the climate crisis has fundamentally altered the shape of politics as usual, you can see how hardline anti-abortion conservatives might be willing to make compromises, as they have already with Tanton-affiliated groups; after all, even now they by and large make little noise about family separation at the border, or the detention and deportation of pregnant asylum-seekers. As anti-abortion fanatic and white nationalist Representative Steve King recently suggested, it’s fine for people to drink water out of toilet bowls in detention centers—that is, presumably, if they’re somebody else’s babies.

A study published this summer surveyed sustainability professors in order to measure just how popular “Tragedy” remains in undergraduate coursework and how exactly it is being taught. The authors found, strangely, that a third of respondents still view Hardin as representing the “foremost thinking” about commons governance despite decades of intervening scholarship and empirical research. But a higher percentage of respondents taught the article for the same reason Hardin wrote it: to underscore the necessity of “external intervention” in order to stave off a tragedy of the commons.

Governments and individuals must act and act urgently to prevent the worst forecasts of our maturing climate crisis. It cannot be done without “external intervention” into the capitalist system that has brought us to this breaking point. And Hardin was not wrong in his insistence on the limits of economic growth, but his preferred interventions are of a different sort entirely; they are authoritarian, and they are ethnonationalist. The “taboo” which Hardin “stalked” around discussions of population and the environment is starting to find its way again into the sights of writers and activists. And it is Hardin’s legacy with which they must contend. They should tread lightly.