It is the best of times for Thought Leaders. It is the worst of times for Public Intellectuals. It is the most confusing of times for those of us in the academy.

Let me unpack these terms. Public Intellectuals are experts, often academics, who are well versed and well trained enough to comment on a wide range of issues. As Friedrich Hayek put it, Public Intellectuals are “professional secondhand dealers in ideas.” Think Paul Krugman or Jill Lepore. A Thought Leader is an intellectual evangelist. They develop their own singular lens to explain the world, and then proselytize to anyone within earshot. Think Robert Kagan or Naomi Klein.

Both Public Intellectuals and Thought Leaders engage in acts of intellectual creation, but their style and purpose are different. To adopt the language of Isaiah Berlin, Public Intellectuals are foxes who know many things, while Thought Leaders are hedgehogs who know one big thing. The former are skeptics, the latter are true believers. A Public Intellectual will tell you everything that is wrong with everyone else’s ideas. A Thought Leader will tell you everything that is right about his or her own idea.Both intellectual types serve a vital purpose in a democracy. Public Intellectuals are often bashed as elitists, but they help to expose shibboleths masquerading as accepted wisdom. They are critics, and critiquing bad ideas is a necessary function. Their greatest contribution to public discourse is to point out when an emperor has no clothes. Thought Leaders, on the other hand, are often derided as glib TED-talkers lacking in substance, but they can introduce and promote new ideas. During times of uncertainty and change, Thought Leaders can offer intellectually stimulating ways to reimagine the world.

A public sphere dominated by Public Intellectuals has high barriers to entry; the marketplace of ideas becomes ossified and stagnant over time. One dominated by Thought Leaders has high barriers to exit; too many bad ideas linger in the intellectual ether. A healthy public discourse in which good ideas rise to the top requires a balance between the two types of thinkers.

In the past few decades, however, the market has become unbalanced. The surge of ideas conferences, speaker bureaus, and TED-like events suggests that the demand for thinkers has grown. The proliferation of media platforms has accelerated that trend. At the same time, the supply of intellectuals has increased far beyond the academy. In foreign policy and economic analysis, the areas I am most familiar with, academics must compete with a welter of think tanks, private-sector outlets, and professional pundits to have their voice heard.

As both demand and supply have increased, the marketplace of ideas has become the Ideas Industry. Promoting ideas in the public sphere has become a big business, as anyone looking at speakers-bureau fees can attest. Furthermore, the Ideas Industry is far more weighted toward Thought Leaders than Public Intellectuals. It is not a coincidence that the private sector has been the biggest booster of the term “thought leadership.” Corporations appreciate the value of branding, a skill that is a comparative advantage of Thought Leaders. The rise of the for-profit Thought Leader has come at the same time that those in the academy have retreated from the public sphere.

The same deep forces that have empowered Thought Leaders have also hampered the academy’s ability to influence the marketplace of ideas. Three factors — the erosion of trust in authority, the increase in political polarization, and growth in economic inequality — have collectively lowered the academy’s public standing. To be sure, many academics have found public outlets in places like Vox, Lawfare, or The Washington Post and The New York Times. Some academics have learned to survive and thrive in the Ideas Industry. Most of the superstars, however, primarily do so by adopting the style of Thought Leaders, thereby tipping the scales even further toward that tribe.

Over the past half-century there has been an erosion of public trust in almost every major American institution except for the military. This includes higher education. In 1974, the average percentage of people who have “a great deal” of confidence in education, according to the General Social Survey, peaked at approximately 50 percent. By 2012 average confidence had dropped to 26 percent.

Scholars attempting to weigh in on public affairs confront a delegitimizing assault on the academy — call it the War on College. Conservatives have been blasting the ivory tower as godless, leftist, and insular since William F. Buckley Jr.’s God and Man at Yale. Recent criticism has focused on speech restrictions. In a cover story for The Atlantic, Greg Lukianoff of the Foundation for Individual Rights in Education and Jonathan Haidt, a social psychologist at New York University’s business school, decried the tendency “to scrub campuses clean of words, ideas, and subjects that might cause discomfort or give offense.” And there is no shortage of appalling anecdotes: From Laura Kipnis, the Northwestern University professor who faced a Title IX inquisition for publicly criticizing the university’s sexual-harassment process, to the unruly group of protesters at Middlebury College who blocked Charles Murray from speaking.

Conservative criticisms of the academy have been a constant for decades. What is more unusual is the vocal criticism coming from the left. Feminists have attacked universities for being havens of sexual assault. Minority groups have critiqued the structural privilege that allegedly pervades elite campuses. Leftists deplore universities as bastions of elitism, sublimating the goal of higher education in favor of appeasing corporate donors.

Consider William Deresiewicz’s much-discussed jeremiad, Excellent Sheep, a critique of the university’s surrender to neoliberalism: “Elite schools like to boast that they teach their students how to think, but all they mean is that they train them in the analytic and rhetorical skills that are necessary for success in business and the professions.” Deresiewicz is hardly alone in holding this view.

The conservative and corporatist critiques are in tension. According to Lukianoff and Haidt, political correctness “teaches students to think in a very different way. It prepares them poorly for professional life, which often demands intellectual engagement with people and ideas one might find uncongenial or wrong.” If this is true, then Deresiewicz is wrong to accuse universities of incubating corporate drones. If Deresiewicz is correct, however, then Lukianoff and Haidt’s hypothesis is exaggerated.The point is that both critiques are flourishing at the same time, evidence of widespread support for the War on College and growing disdain for the professoriate. Simply put, it’s easier than ever to dismiss academic interventions in the public sphere.

The growth of political polarization in the United States is another cause of imbalance in the ideas industry. An orgy of evidence demonstrates that we are at peak partisanship. Political elites are now more ideologically extreme than at any time in postwar history. Experimental research suggests that partisans are more likely to discriminate based on political differences than on race or gender.

Rising partisanship has happened just as academics have drifted further to the left. Whether one looks at survey data, voter registration, or campaign contributions, the results are incontrovertible: American academics are far more liberal than the rest of the country. That divergence has increased over the past 25 years. According to UCLA’s Higher Education Research Institute, in 1990 the number of self-identified liberals and leftists in academe was roughly equal to the number of moderates. By 2010 there were twice as many liberals as moderates, and almost six times as many liberals as conservatives. If one looks only at the social sciences and the humanities, these ratios are even more stacked in favor of liberals and the left.

Just because scholars have political preferences doesn’t mean their work is compromised, but those preferences do bias the questions they ask. One study of social psychologists concluded that the sharp leftward tilt of the field did not invalidate existing research, but it did alter the direction of future scholarship: “Researchers may concentrate on topics that validate the liberal progress narrative and avoid topics that contest that narrative.” Sociology suffers from a similar problem. Another study concluded that the leftist leanings of sociologists “compresses the range of acceptable scholarship, and constrains sociological insight.” These problems are hardly unique to these disciplines; other research has demonstrated a link between a scholar’s political tilt and the trajectory of his or her research in both law and international relations.

The leftward drift of the academy gives conservatives an easy way to deride academic interventions in the public sphere. Frederick M. Hess, director of education-policy studies at the American Enterprise Institute, told The Washington Post recently that, “to me, university leadership has felt enormously partisan.” In response to university-based criticisms of the Trump administration, Hess said that ideological homogeneity on campus, “factors into seeing this as cheap partisan thuggery rather than any serious commitment to robust civic debate.” In a survey of foreign-policy elites that I conducted, conservatives were far more skeptical about the validity of social-science research than were moderates or liberals.

Economic inequality is a third factor fueling academe’s shrinking influence on the public sphere. In the last few years, a new class of benefactors has emerged that university presidents can woo to bolster their endowments. Indeed, university administrators have retreated from public life in large part because they have become full-time fund raisers. The modern marketplace of ideas has made their job more challenging. First, it’s difficult to speak truth to money; universities need to please wealthy benefactors. Second, a growing number of potential benefactors have spurned the academy. Some Silicon Valley billionaires like Peter Thiel argue that higher education actually retards intellectual progress. He pays people to skip college. Most modern plutocrats are not so extreme, but their style does differ from the Rockefellers and Carnegies of yesteryear. The new philanthrocapitalists are interested in “impact” investments — they want their giving to have a direct effect on the world. They want universities to sponsor research or teaching that addresses their views, like requiring Ayn Rand’s Atlas Shrugged to be taught in classes. As the Brookings Institution’s Darrell West notes, because of the preconceived worldviews of these philanthrocapitalists, “it is becoming harder to separate academic philanthropy from advocacy.”

The desire for action clashes with the academic impulse for detachment. Academics typically intervene in the marketplace of ideas as traditional Public Intellectuals ready to explain why some new policy idea is unlikely to work. Patrons would much rather bankroll Thought Leaders because they possess two qualities that benefactors like: positive ideas for change, and the conviction that they can make a difference.

This gap between professors and doers goes back to Max Weber’s “Science as a Vocation,” in which he implored professors to keep their academic tasks separate from other spheres of life, especially politics. Not to say that academics couldn’t engage the public, but Weber noted that the primary task of a professor was to “teach his students to recognize ‘inconvenient’ facts.” Weber further argued that political action was a different activity altogether: “The qualities that make a man an excellent scholar and academic teacher are not the qualities that make him a leader to give directions in practical life, or, more specifically, in politics.” An academic acting as a Public Intellectual is trying to straddle both of these roles, and risks doing both poorly.

The academics most likely to thrive in the Ideas Industry are those who adopt the tropes of Thought Leaders. The Harvard Business School professor Clayton Christensen, for example, has built an intellectual empire around the idea of disruptive innovation. The degree of self-confidence a scholar projects shapes how others perceive that scholar’s arguments. As much as scholarship is supposed to count über alles, there is no denying that assertive scholars can sway opinion. One reason that economists are more influential than other social scientists is that, as Dani Rodrik notes, economists who talk to the public act more like hedgehogs than foxes.

I know economists who make fantastically bold predictions, and I envy their serene conviction that they are right despite ample reasons for doubt. In the past decade, economists have made serious mistakes on issues like asset bubbles, financial deregulation, and whether free trade in an unambiguous good. The discipline has yet to engage in much introspection.

A marketplace of ideas with stronger universities would be one that empowered traditional Public Intellectuals. But distrust in expertise, political polarization, and the rise in economic inequality are decades-long trends that are unlikely to reverse themselves anytime soon. All of these trends will harm Public Intellectuals at the expense of Thought Leaders. In the face of these gale-force winds of change, is there anything academe can do to preserve a space for traditional Public Intellectuals?

Acknowledging the problems would be a good first step. Universities can encourage scholars to monitor their own disciplines so as to reduce the number of academic scandals. They can demonstrate greater tolerance for conservative points of view on campus. They can cultivate an emergent cluster of organizations like the Tobin Project or Bridging the Gap, which help academics get their ideas before the public.

In the end, however, universities also need to revive their institutional prestige. It is worth remembering that American higher education remains the global leader in just about every discipline. Skeptics who doubt the utility of colleges should be reminded that higher education is one of America’s leading export sectors, running a $35-billion surplus in 2015. A recent joint letter by university chancellors protesting the Trump administration’s immigration ban points this out. It is also a welcome display of university presidents re-entering the public sphere. Administrators could also persuade philanthropic foundations to care a little less about immediate impact and a little more about long-term investments in intellectual capital.

It will not be easy for university leaders and academics to balance the confidence of Thought Leaders with the self-criticism of Public Intellectuals. This requires a complex equipoise. On the other hand, professors are good at appreciating shades of gray. We should embrace this additional layer of complexity.

Daniel W. Drezner is professor of international politics at the Fletcher School of Law and Diplomacy at Tufts University. This essay is adapted from his book The Ideas Industry: How Pessimists, Partisans, and Plutocrats are Transforming the Marketplace of Ideas, just out from Oxford University Press.