Free speech in the United States is in trouble. An open letter signed by more than 150 prominent people stated the problem: “The free exchange of information and ideas, the lifeblood of a liberal society, is daily becoming more constricted,” they wrote, through “an intolerance of opposing views, a vogue for public shaming and ostracism, and the tendency to dissolve complex policy issues in a blinding moral certainty.”

This development is surprising, for three reasons. It is surprising, first, because it is taking place in the United States, a country founded on freedom. Its founders used the synonym for freedom, “liberty,” and they and their successors considered it so important that the word is imprinted on American coins. Of the several varieties of liberty, moreover, freedom of speech has traditionally occupied the preeminent place in America: Among the rights enshrined in the Constitution’s Bill of Rights, freedom of speech is guaranteed in the First.

The assault on free speech is surprising, too, because it is taking place within two institutions founded on that very liberty, the press and the academy. Indeed, the two could hardly exist without it. Yet now it is there that it is under the most virulent attack. Third, while restrictions on speech are all too common around the world, in most countries it is the government that imposes them. In the United States, by contrast, the campaign against freedom of speech comes not from above but from below, from the aggressive tactics of majorities—or militant, intimidating minorities—within these institutions.

This last feature makes a classic defense of freedom particularly relevant to current circumstances, the English writer John Stuart Mill’s 1859 essay On Liberty. Mill worried about the same threat to individual liberty that his French contemporary, Alexis de Tocqueville, identified in his own classic, Democracy in America: the tyranny of the majority. As the public as a whole became more active and powerful socially and politically—which both men saw as a dominant and presumably irreversible trend—they feared that it would use its weight to suppress opinions that it regarded as unworthy or dangerous. That is precisely what the “woke” Twitter mobs and their allies have been doing in American universities and the media.

On Liberty is an apt text for the present moment in another way. For Mill, liberty’s claim to protection rested not on its intrinsic importance but rather on its contribution to a higher good. That higher good was progress of the kind that expanded human welfare, which Mill defined as the greatest happiness for the greatest number. Here he differed from the founders of the United States, who considered freedom to be valuable for its own sake, something due to every person. In their Declaration of Independence of 1776, they deemed it self-evident that all people were “endowed by their Creator with certain unalienable Rights.” Among these rights they mentioned liberty second, after life and before the pursuit of happiness.

Although their views are not models of clarity on this point, the present-day speech police apparently agree with Mill and not the founders of their own country. For them, too, expression is not a right—otherwise they would not seek to curtail it—but instead something to be permitted only insofar as it serves their higher purpose. That purpose is what they term “social justice,” which seems to involve mainly considerations of race, ethnicity, and gender. 

It is an interesting question just how it came to pass that an idea— justice—that has received the intense attention of some of the most acute minds in human history without yielding a consensus on its precise nature, has now received from Yale sophomores and junior editors at The New York Times a definition that, at least in their view, is authoritative and worthy of universal assent. Granting for the moment the dubious proposition that they have appropriately defined justice, however, Mill’s defense of liberty of expression becomes pertinent. For him, liberty of expression and inquiry is necessary for what he values most; and so logically it should be as well for the current self-appointed arbiters of academic and journalistic orthodoxy.

Mill makes a straightforward case for such liberty, which amounts to a version of the scientific method. An opinion or assertion may be true, but if so it will draw strength, conviction, and validity from being tested. Or it may be false and in need of correction, for which open investigation is necessary. Or it may be an amalgam of truth and falsehood, in which case the two must be differentiated. Mill’s central point is that testing, correction, and differentiation, all of them indispensable for the higher cause of progress contributing to human happiness, all require liberty of thought, of inquiry, and of expression.

So it ought also to be, given what they profess as their goal, for the woke mob. It is, for example, an empirical question whether defunding and thus abolishing the police, a current demand in some quarters, will enhance the justice of American society by bringing benefits to the groups whose interests justice requires serving. (Spoiler alert: it won’t.) Empirical questions can only be answered by research, discussion, criticism, and more research. Stifling them, therefore, by the very standards of the woke mob, contributes to injustice.

The relevance of Mill’s arguments for liberty in the present context assumes that the assailants of free speech are motivated exclusively by the quest for social justice. That is perhaps an overly generous assumption. Other motives may well be at work: a cynical effort to acquire more power within the institutions under assault, for instance, or the sadistic enjoyment that comes from successful bullying.

To the extent that these other, less worthy impulses are in play, the protection of liberty of expression does not require well-wrought arguments on its behalf of the kind that Mill provides. What is needed, instead, is a determined defense of free speech by the guardians of the institutions in which it is under siege—the presidents, trustees, and deans of universities and the owners and editors of newspapers—who ought to understand, and in most cases surely do understand, its surpassing importance for their institutions. What is now required, that is, is something that has been conspicuous by its absence among such people recently: simple civic courage. Unfortunately, for today’s urgent task of mobilizing civic courage, On Liberty offers no useful advice.