My liberal friends sometimes ask me why I don’t devote more of my science journalism to the sins of the Right. It’s fine to expose pseudoscience on the left, they say, but why aren’t you an equal-opportunity debunker? Why not write about conservatives’ threat to science?

My friends don’t like my answer: because there isn’t much to write about. Conservatives just don’t have that much impact on science. I know that sounds strange to Democrats who decry Republican creationists and call themselves the “party of science.” But I’ve done my homework. I’ve read the Left’s indictments, including Chris Mooney’s bestseller, The Republican War on Science. I finished it with the same question about this war that I had at the outset: Where are the casualties?

Where are the scientists who lost their jobs or their funding? What vital research has been corrupted or suppressed? What scientific debate has been silenced? Yes, the book reveals that Republican creationists exist, but they don’t affect the biologists or anthropologists studying evolution. Yes, George W. Bush refused federal funding for embryonic stem-cell research, but that hardly put a stop to it (and not much changed after Barack Obama reversed the policy). Mooney rails at scientists and politicians who oppose government policies favored by progressives like himself, but if you’re looking for serious damage to the enterprise of science, he offers only three examples.

All three are in his first chapter, during Mooney’s brief acknowledgment that leftists “here and there” have been guilty of “science abuse.” First, there’s the Left’s opposition to genetically modified foods, which stifled research into what could have been a second Green Revolution to feed Africa. Second, there’s the campaign by animal-rights activists against medical researchers, whose work has already been hampered and would be devastated if the activists succeeded in banning animal experimentation. Third, there’s the resistance in academia to studying the genetic underpinnings of human behavior, which has cut off many social scientists from the recent revolutions in genetics and neuroscience. Each of these abuses is far more significant than anything done by conservatives, and there are plenty of others. The only successful war on science is the one waged by the Left.

The danger from the Left does not arise from stupidity or dishonesty; those failings are bipartisan. Some surveys show that Republicans, particularly libertarians, are more scientifically literate than Democrats, but there’s plenty of ignorance all around. Both sides cherry-pick research and misrepresent evidence to support their agendas. Whoever’s in power, the White House plays politics in appointing advisory commissions and editing the executive summaries of their reports. Scientists of all ideologies exaggerate the importance of their own research and seek results that will bring them more attention and funding.

But two huge threats to science are peculiar to the Left—and they’re getting worse.

The first threat is confirmation bias, the well-documented tendency of people to seek out and accept information that confirms their beliefs and prejudices. In a classic study of peer review, 75 psychologists were asked to referee a paper about the mental health of left-wing student activists. Some referees saw a version of the paper showing that the student activists’ mental health was above normal; others saw different data, showing it to be below normal. Sure enough, the more liberal referees were more likely to recommend publishing the paper favorable to the left-wing activists. When the conclusion went the other way, they quickly found problems with its methodology.

Scientists try to avoid confirmation bias by exposing their work to peer review by critics with different views, but it’s increasingly difficult for liberals to find such critics. Academics have traditionally leaned left politically, and many fields have essentially become monocultures, especially in the social sciences, where Democrats now outnumber Republicans by at least 8 to 1. (In sociology, where the ratio is 44 to 1, a student is much likelier to be taught by a Marxist than by a Republican.) The lopsided ratio has led to another well-documented phenomenon: people’s beliefs become more extreme when they’re surrounded by like-minded colleagues. They come to assume that their opinions are not only the norm but also the truth.

Groupthink has become so routine that many scientists aren’t even aware of it. Social psychologists, who have extensively studied conscious and unconscious biases against out-groups, are quick to blame these biases for the underrepresentation of women or minorities in the business world and other institutions. But they’ve been mostly oblivious to their own diversity problem, which is vastly larger. Democrats outnumber Republicans at least 12 to 1 (perhaps 40 to 1) in social psychology, creating what Jonathan Haidt calls a “tribal-moral community” with its own “sacred values” about what’s worth studying and what’s taboo.

“Morality binds and blinds,” says Haidt, a social psychologist at New York University and author of The Righteous Mind: Why Good People Are Divided by Politics and Religion. “Having common values makes a group cohesive, which can be quite useful, but it’s the last thing that should happen to a scientific field. Progressivism, especially anti-racism, has become a fundamentalist religion, complete with anti-blasphemy laws.”

Last year, one of the leading scientific journals, Behavioral and Brain Sciences, published an article by Haidt and five colleagues documenting their profession’s lack of ideological diversity. It was accompanied by commentaries from 63 other social scientists, virtually all of whom, even the harshest critics, accepted the authors’ conclusion that the lack of political diversity has harmed the science of social psychology. The authors and the commentators pointed to example after example of how the absence of conservatives has blinded researchers to flaws in their work, particularly when studying people’s ideology and morality.

Democrats outnumber Republicans at least 12 to 1 (perhaps 40 to 1) in social psychology.

The narrative that Republicans are antiscience has been fed by well-publicized studies reporting that conservatives are more close-minded and dogmatic than liberals are. But these conclusions have been based on questions asking people how strongly they cling to traditional morality and religion—dogmas that matter a lot more to conservatives than to liberals. A few other studies—not well-publicized—have shown that liberals can be just as close-minded when their own beliefs, such as their feelings about the environment or Barack Obama, are challenged.

Social psychologists have often reported that conservatives are more prejudiced against other social groups than liberals are. But one of Haidt’s coauthors, Jarret Crawford of the College of New Jersey, recently noted a glaring problem with these studies: they typically involve attitudes toward groups that lean left, like African-Americans and communists. When Crawford (who is a liberal) did his own study involving a wider range of groups, he found that prejudice is bipartisan. Liberals display strong prejudice against religious Christians and other groups they perceive as right of center.

Conservatives have been variously pathologized as unethical, antisocial, and irrational simply because they don’t share beliefs that seem self-evident to liberals. For instance, one study explored ethical decision making by asking people whether they would formally support a female colleague’s complaint of sexual harassment. There was no way to know if the complaint was justified, but anyone who didn’t automatically side with the woman was put in the unethical category. Another study asked people whether they believed that “in the long run, hard work usually brings a better life”—and then classified a yes answer as a “rationalization of inequality.” Another study asked people if they agreed that “the Earth has plenty of natural resources if we just learn how to develop them”—a view held by many experts in resource economics, but the psychologists pathologized it as a “denial of environmental realities.”

To combat these biases, more than 150 social scientists have joined Heterodox Academy, a group formed by Haidt and his coauthors to promote ideological diversity among scholars. That’s a good start, but they’re nowhere close to solving the problem. Even if social-science departments added a few conservatives, they’d still be immersed in progressive academic communities becoming less tolerant of debate because of pressure from campus activists and federal bureaucrats enforcing an ever-expanding interpretation of Title IX. And their work would still be filtered to the public by reporters who lean left, too—that’s why the press has promoted the Republican-war-on-science myth. When Obama diplomatically ducked a question on the campaign trail about the age of the Earth (“I don’t presume to know”), the press paid no attention. When Marco Rubio later did the same thing (“I’m not a scientist”), he was lambasted as a typical Republican ignoramus determined to bring back the Dark Ages.

The combination of all these pressures from the Left has repeatedly skewed science over the past half-century. In 1965, when Daniel Patrick Moynihan published a paper presciently warning of the dangers for black children growing up in single-parent homes, it was greeted with such hostility—he was blaming the victim, critics said—that the topic became off-limits among liberals, stymying public discussion and research for decades into one of the most pressing problems facing minority children. Similarly, liberal advocates have worked to suppress reporting on the problems of children raised by gay parents or on any drawbacks of putting young children in day care. In 1991, a leading family psychologist, Louise Silverstein, published an article in the American Psychologist urging her colleagues to “refuse to undertake any more research that looks for the negative consequences of other-than-mother-care.”

The Left’s most rigid taboos involve the biology of race and gender, as the Harvard psychologist Steven Pinker chronicles in The Blank Slate. The book takes its title from Pinker’s term for the dogma that “any differences we see among races, ethnic groups, sexes, and individuals come not from differences in their innate constitution but from differences in their experiences.” The dogma constricts researchers’ perspective—“No biology, please, we’re social scientists”—and discourages debate, in and out of academia. Early researchers in sociobiology faced vitriolic attacks from prominent scientists like Stephen Jay Gould, who accused them of racism and sexism for studying genetic influences on behavior.

Studying IQ has been a risky career move since the 1970s, when researchers like Arthur Jensen and Richard Herrnstein had to cancel lectures (and sometimes hire bodyguards) because of angry protesters accusing them of racism. Government funding dried up, forcing researchers in IQ and behavioral genetics to rely on private donors, who in the 1980s financed the renowned Minnesota study of twins reared apart. Leftists tried to cut off that funding in the 1990s, when the University of Delaware halted the IQ research of Linda Gottfredson and Jan Blits for two years by refusing to let them accept a foundation’s grant; the research proceeded only after an arbitrator ruled that their academic freedom had been violated.

The Blank Slate dogma has perpetuated a liberal version of creationism: the belief that there has been no evolution in modern humans since they left their ancestral homeland in Africa some 50,000 years ago. Except for a few genetic changes in skin color and other superficial qualities, humans everywhere are supposedly alike because there hasn’t been enough time for significant differences to evolve in their brains and innate behavior. This belief was plausible when biologists assumed that evolution was a slow process, but the decoding of the human genome has disproved it, as Nicholas Wade (a former colleague of mine at the New York Times) reported in his 2015 book, A Troublesome Inheritance.

“Human evolution has been recent, copious and regional,” writes Wade, noting that at least 8 percent of the human genome has changed since the departure from Africa. The new analysis has revealed five distinguishable races that evolved in response to regional conditions: Africans, East Asians, Caucasians, the natives of the Americas, and the peoples of Australia and Papua New Guinea. Yet social scientists go on denying the very existence of races. The American Anthropological Association declares race to be “a human invention” that is “about culture, not biology.” The American Sociological Association calls race a “social construct.” Even biologists and geneticists are afraid of the R-word. More than 100 of them sent a letter to the New York Times denouncing Wade’s book as inaccurate, yet they refused to provide any examples of his mistakes. They apparently hadn’t bothered to read the book because they accused Wade of linking racial variations to IQ scores—a link that his book specifically rejected.

Some genetic differences are politically acceptable on the left, such as the biological basis for homosexuality, which was deemed plausible by 70 percent of sociologists in a recent survey. But that same survey found that only 43 percent accepted a biological explanation for male-female differences in spatial skills and communication. How could the rest of the sociologists deny the role of biology? It was no coincidence that these doubters espoused the most extreme left-wing political views and the strongest commitment to a feminist perspective. To dedicated leftists and feminists, it doesn’t matter how much evidence of sexual differences is produced by developmental psychologists, primatologists, neuroscientists, and other researchers. Any disparity between the sexes—or, at least, any disparity unfavorable to women—must be blamed on discrimination and other cultural factors.

Former Harvard president Lawrence Summers found this out the hard way at an academic conference where he dared to discuss the preponderance of men among professors of mathematics and physical sciences at elite universities. While acknowledging that women faced cultural barriers, like discrimination and the pressures of family responsibilities, Summers hypothesized that there might be other factors, too, such as the greater number of men at the extreme high end in tests measuring mathematical ability and other traits. Males’ greater variability in aptitude is well established—it’s why there are more male dunces as well as geniuses—but scientific accuracy was no defense against the feminist outcry. The controversy forced Summers to apologize and ultimately contributed to his resignation. Besides violating the Blank Slate taboo, Summers had threatened an academic cottage industry kept alive by the myth that gender disparities in science are due to discrimination.

This industry, supported by more than $200 million from the National Science Foundation, persists despite overwhelming evidence—from experiments as well as extensive studies of who gets academic jobs and research grants—that a female scientist is treated as well as or better than an equally qualified male. In a rigorous set of five experiments published last year, the female candidate was preferred two-to-one over an equivalent male. The main reason for sexual disparities in some fields is a difference in interests: from an early age, more males are more interested in fields like physics and engineering, while more females are interested in fields like biology and psychology (where most doctorates go to women).

On the whole, American women are doing much better than men academically—they receive the majority of undergraduate and graduate degrees—yet education researchers and federal funders have focused for decades on the few fields in science where men predominate. It was bad enough that the National Science Foundation’s grants paid for workshops featuring a game called Gender Bias Bingo and skits in which arrogant male scientists mistreat smarter female colleagues. But then, these workshops nearly became mandatory when Democrats controlled Congress in 2010. In response to feminist lobbying, the House passed a bill (which fortunately died in the Senate) requiring federal science agencies to hold “gender equity” workshops for the recipients of research grants.

It might seem odd that the “party of science” would be dragging researchers out of the lab to be reeducated in games of Gender Bias Bingo. But politicians will always care more about pleasing constituencies than advancing science.

And that brings us to the second great threat from the Left: its long tradition of mixing science and politics. To conservatives, the fundamental problem with the Left is what Friedrich Hayek called the fatal conceit: the delusion that experts are wise enough to redesign society. Conservatives distrust central planners, preferring to rely on traditional institutions that protect individuals’ “natural rights” against the power of the state. Leftists have much more confidence in experts and the state. Engels argued for “scientific socialism,” a redesign of society supposedly based on the scientific method. Communist intellectuals planned to mold the New Soviet Man. Progressives yearned for a society guided by impartial agencies unconstrained by old-fashioned politics and religion. Herbert Croly, founder of the New Republic and a leading light of progressivism, predicted that a “better future would derive from the beneficent activities of expert social engineers who would bring to the service of social ideals all the technical resources which research could discover.”

This was all very flattering to scientists, one reason that so many of them leaned left. The Right cited scientific work when useful, but it didn’t enlist science to remake society—it still preferred guidance from traditional moralists and clerics. The Left saw scientists as the new high priests, offering them prestige, money, and power. The power too often corrupted. Over and over, scientists yielded to the temptation to exaggerate their expertise and moral authority, sometimes for horrendous purposes.

Drawing on research into genetics and animal breeding from scientists at Harvard, Yale, Johns Hopkins, and other leading universities, the eugenics movement of the 1920s made plans for improving the human population. Professors taught eugenics to their students and worked with Croly and other progressives eager to breed a smarter society, including Theodore Roosevelt, Woodrow Wilson, and Margaret Sanger. Eventually, other scientists—notably, in England—exposed the shoddy research and assumptions of the eugenicists, but not before the involuntary sterilization or castration of more than 35,000 Americans. Even after Hitler used eugenics to justify killing millions, the Left didn’t lose its interest in controlling human breeding.

Eugenicist thinking was revived by scientists convinced that the human species had exceeded the “carrying capacity” of its ecosystem. The most prominent was Paul Ehrlich, whose scientific specialty was the study of butterflies. Undeterred by his ignorance of agriculture and economics, he published confident predictions of imminent global famine in The Population Bomb (1968). Agricultural economists dismissed his ideas, but the press reverently quoted Ehrlich and other academics who claimed to have scientifically determined that the Earth was “overpopulated.” In the journal Science, ecologist Garrett Hardin argued that “freedom to breed will bring ruin to all.” Ehrlich, who, at one point, advocated supplying American helicopters and doctors to a proposed program of compulsory sterilization in India, joined with physicist John Holdren in arguing that the U.S. Constitution would permit population control, including limits on family size and forced abortions. Ehrlich and Holdren calmly analyzed the merits of various technologies, such as adding sterilants to public drinking water, and called for a “planetary regime” to control population and natural resources around the world.

Environmental science has become so politicized that its myths endure even after they’ve been disproved.

Their ideas went nowhere in the United States, but they inspired one of the worst human rights violations of the twentieth century, in China: the one-child policy, resulting in coerced abortion and female infanticide. China struggles today with a dangerously small number of workers to support its aging population. The intellectual godfathers of this atrocity, had they been conservatives, surely would have been ostracized. But even after his predictions turned out to be wildly wrong, Ehrlich went on collecting honors.

For his part, Holdren has served for the past eight years as the science advisor to President Obama, a position from which he laments that Americans don’t take his warnings on climate change seriously. He doesn’t seem to realize that public skepticism has a lot to do with the dismal track record of himself and his fellow environmentalists. There’s always an apocalypse requiring the expansion of state power. The visions of global famine were followed by more failed predictions, such as an “age of scarcity” due to vanishing supplies of energy and natural resources and epidemics of cancer and infertility caused by synthetic chemicals. In a 1976 book, The Genesis Strategy, the climatologist Stephen Schneider advocated a new fourth branch of the federal government (with experts like himself serving 20-year terms) to deal with the imminent crisis of global cooling. He later switched to become a leader in the global-warming debate.

Environmental science has become so politicized that its myths endure even after they’ve been disproved. Rachel Carson’s Silent Spring set off decades of chemophobia with its scary anecdotes and bad science, like her baseless claim that DDT was causing cancer in humans and her vision of a mass avian die-off (the bird population was actually increasing as she wrote). Yet Silent Spring is taught in high school and college courses as a model of science writing, with no mention of the increased death tolls from malaria in countries that restricted DDT, or of other problems—like the spread of dengue and the Zika virus—exacerbated by needless fears of insecticides. Similarly, the Left’s zeal to find new reasons to regulate has led to pseudoscientific scaremongering about “Frankenfoods,” transfats, BPA in plastic, mobile phones, electronic cigarettes, power lines, fracking, and nuclear energy.

The health establishment spent decades advocating a low-salt diet for everyone (and pressuring the food industry to reduce salt) without any proof that it prolonged lives. When researchers finally got around to doing small clinical trials, they found that the low-salt diet did not prolong lives. If anything, it was associated with higher mortality. The worst debacle in health science involved dietary fat, which became an official public enemy in the 1970s, thanks to a few self-promoting scientists and politically savvy activists who allied with Democrats in Congress led by George McGovern and Henry Waxman. The supposed link between high-fat diets and heart disease was based on cherry-picked epidemiology, but the federal government endorsed it by publishing formal “dietary goals for the United States” and creating the now-infamous food pyramid that encouraged Americans to replace fat in their diets with carbohydrates. The public-health establishment devoted its efforts and funding to demonstrating the benefits of low-fat diets. But the low-fat diet repeatedly flunked clinical trials, and the government’s encouragement of carbohydrates probably contributed to rising rates of obesity and diabetes, as journalists Gary Taubes and Nina Teicholz have chronicled in their books. (See “The Washington Diet,” Spring 2011.)

The dietary-fat debate is a case study in scientific groupthink—and in the Left’s techniques for enforcing political orthodoxy. From the start, prominent nutrition researchers disputed fat’s link to heart disease and criticized Washington for running a dietary experiment on the entire population. But they were dismissed as outliers who’d been corrupted by corporate money. At one hearing, Senator McGovern rebutted the skeptics by citing a survey showing that low-fat diet recommendations were endorsed by 92 percent of “the world’s leading doctors.” Federal bureaucrats and activists smeared skeptics by leaking information to the press about their consulting work with the food industry. One skeptic, Robert Olson of Washington University, protested that during his career, he had received $250,000 from the food industry versus more than $10 million from federal agencies, including ones promoting low-fat diets. If he could be bought, he said, it would be more accurate to call him “a tool of government.” As usual, though, the liberal press focused only on corporate money.

These same sneer-and-smear techniques predominate in the debate over climate change. President Obama promotes his green agenda by announcing that “the debate is settled,” and he denounces “climate deniers” by claiming that 97 percent of scientists believe that global warming is dangerous. His statements are false. While the greenhouse effect is undeniably real, and while most scientists agree that there has been a rise in global temperatures caused in some part by human emissions of carbon dioxide, no one knows how much more warming will occur this century or whether it will be dangerous. How could the science be settled when there have been dozens of computer models of how carbon dioxide affects the climate? And when most of the models overestimated how much warming should have occurred by now? These failed predictions, as well as recent research into the effects of water vapor on temperatures, have caused many scientists to lower their projections of future warming. Some “luke-warmists” suggest that future temperature increases will be relatively modest and prove to be a net benefit, at least in the short term.

The long-term risks are certainly worth studying, but no matter whose predictions you trust, climate science provides no justification for Obama’s green agenda—or anyone else’s agenda. Even if it were somehow proved that high-end estimates for future global warming are accurate, that wouldn’t imply that Greens have the right practical solution for reducing carbon emissions—or that we even need to reduce those emissions. Policies for dealing with global warming vary according to political beliefs, economic assumptions, social priorities, and moral principles. Would regulating carbon dioxide stifle economic growth and give too much power to the state? Is it moral to impose sacrifices on poor people to keep temperatures a little cooler for their descendants, who will presumably be many times richer? Are there more important problems to address first? These aren’t questions with scientifically correct answers.

Yet many climate researchers are passing off their political opinions as science, just as Obama does, and they’re even using that absurdly unscientific term “denier” as if they were priests guarding some eternal truth. Science advances by continually challenging and testing hypotheses, but the modern Left has become obsessed with silencing heretics. In a letter to Attorney General Loretta Lynch last year, 20 climate scientists urged her to use federal racketeering laws to prosecute corporations and think tanks that have “deceived the American people about the risks of climate change.” Similar assaults on free speech are endorsed in the Democratic Party’s 2016 platform, which calls for prosecution of companies that make “misleading” statements about “the scientific reality of climate change.” A group of Democratic state attorneys general coordinated an assault on climate skeptics by subpoenaing records from fossil-fuel companies and free-market think tanks, supposedly as part of investigations to prosecute corporate fraud. Such prosecutions may go nowhere in court—they’re blatant violations of the First Amendment—but that’s not their purpose. By demanding a decade’s worth of e-mail and other records, the Democratic inquisitors and their scientist allies want to harass climate dissidents and intimidate their donors.

Just as in the debate over dietary fat, these dissidents get smeared in the press as corporate shills—but once again, the money flows almost entirely the other way. The most vocal critics of climate dogma are a half-dozen think tanks that together spend less than $15 million annually on environmental issues. The half-dozen major green groups spend more than $500 million, and the federal government spends $10 billion on climate research and technology to reduce emissions. Add it up, and it’s clear that scientists face tremendous pressure to support the “consensus” on reducing carbon emissions, as Judith Curry, a climatologist at Georgia Tech, testified last year at a Senate hearing.

“This pressure comes not only from politicians but also from federal funding agencies, universities and professional societies, and scientists themselves who are green activists,” Curry said. “This advocacy extends to the professional societies that publish journals and organize conferences. Policy advocacy, combined with understating the uncertainties, risks destroying science’s reputation for honesty and objectivity—without which scientists become regarded as merely another lobbyist group.”

That’s the ultimate casualty in the Left’s war: scientists’ reputations. Bad research can be exposed and discarded, but bad reputations endure. Social scientists are already regarded in Washington as an arm of the Democratic Party, so their research is dismissed as partisan even when it’s not, and some Republicans have tried (unsuccessfully) to cut off all social-science funding. The physical sciences still enjoy bipartisan support, but that’s being eroded by the green politicking, and climate scientists’ standing will plummet if the proclaimed consensus turns out to be wrong.

To preserve their integrity, scientists should avoid politics and embrace the skeptical rigor that their profession requires. They need to start welcoming conservatives and others who will spot their biases and violate their taboos. Making these changes won’t be easy, but the first step is simple: stop pretending that the threats to science are coming from the Right. Look in the other direction—or in the mirror.

Top Photo: Objecting to Oxford’s biomedical research, the Animal Liberation Front firebombed a university building. (KIRSTY WIGGLESWORTH/AP PHOTO)