50 years ago this fall, in the midst of an immense upheaval over the role of American institutions in perpetuating racial inequality, one such institution, the City University of New York, embarked on a radical transformation.

Protestors, who had been staging increasingly violent strikes, had assailed City College, CUNY’s flagship school, located in the middle of Harlem, as a racist institution that used academic standards to deny admission to all but a handful of Black and Puerto Rican students. They demanded that CUNY abandon those standards in order to admit students of color in numbers that reflected their enrollment in New York City’s public schools.

City College was a storied place that had served as an engine of social mobility for generations of poor New Yorkers, most notably in the 1930s, when many of the students were Jewish.

The school, in effect, was now being called on to provide the same service to a new generation of disadvantaged students, this time Black and brown. CUNY had already adopted and expanded a program designed to admit more minority students without compromising academic standards, but at a moment when all demands were phrased in absolute terms — and as demands — incremental solutions had no chance. In the fall of 1970, City University agreed to adopt an “open enrollment” system that offered access to every single graduate of New York City public high schools, whatever their level of academic preparation.

I recounted that fateful moment and its tragic consequences in City on a Hill, a book published a quarter-century ago. And I am reminded of it now, because we seem to be at the dawn of a similar moment of institutional upheaval.

The Black Lives Matter movement has kindled hopes for radical change, just as did the anti-war and civil rights demonstrations of that earlier time. A root-and-branch transformation of police culture and tactics, which had barely registered in political debate a few months ago, now seems within reach.

But sweeping revolutions do not stay within their banks.

Activists have increasingly turned from the intransigent and sometimes overtly racist institutions of public order to target the liberal institutions that shape the nation’s culture and conversation — museums, universities, newspapers. These institutions are far more vulnerable to demands than are police departments, in part because they are more sympathetic to those demands. They may, in fact, prove to be surprisingly helpless in defending what is alleged to be a profoundly entrenched order.

Today, as 50 years ago, we have embarked on a politics of accusation in which both individuals and institutions are being called on to acknowledge their complicity with injustice. Many of those accusations are as well-founded today as they were in the late sixties. Institutions are rightly called to account for efforts to recruit and promote Black candidates that were, at least until recently, half-hearted. White people generally are called to examine implicit biases that have shaped their behavior towards their black colleagues.

Yet a politics of accusation requires villains. While out-and-out racists are hard to find in liberal institutions, merely expressing qualms about the new orthodoxy or failing to honor its precepts is now taken as evidence of racism. It is, in fact, the premise of books like Robin DiAngelo’s White Fragility, and of the “anti-racist” training that such works have spawned: that virtually all institutions are infected with white supremacy. Already, alleged perpetrators have begun to fall; the list of newspapers editors and museum leaders and think tank researchers who have been fired is already so notorious that The Letter defending free speech recently published in Harper’s didn’t even bother to name names.

Thanks to best-selling polemics like White Fragility, we also know all too well the terms of the current battle over whether some liberal principles must be sacrificed in order to uproot racism. But we have not yet given enough thought to the danger this new orthodoxy poses to the core mission of some of the institutions where it has most deeply taken root.

The experience of City University of New York half a century ago reminds us of those very real dangers. In speaking with veterans of the struggle over open enrollment, I was often struck by the anguish of left-wing professors who had automatically identified with the underdog and the protestors, and yet had not believed that open admissions could possibly work as envisioned. They believed that students at inner-city high schools had been so poorly educated for so long that no college would be able to offer them the kind of remedial education that would need to succeed. Open enrollment, they argued in the midst of a brutal debate, “would destroy City College and . . . perpetrate a cruel hoax on the young people so admitted.” At the time, they were all denounced as reactionaries, and reviled as racists who did not believe that Black and brown students were smart enough to meet the rigorous standards of City College.

I began my research hoping to find that these predictions had been too dire, and that City had managed to become more inclusive while maintaining high standards. But that wasn’t true. 20 years later, as the critics had feared, City had become a largely remedial institution with dismal graduation rates for those who required remediation. (City has since become a far more rigorous and impressive institution, in part because CUNY jettisoned open admissions and delegated remediation to the city’s community colleges, as the moderates had proposed in 1970.)

The story of City College reminds us that many institutions, however entrenched they may seem, are actually quite fragile. To demand that such institutions simply exchange their existing culture for one that satisfies the terms of a new ideology is to court their destruction.

Of course, some institutions need to be re-built from the ground up. But universities and museums are not police departments, or the Pentagon, or the Trump Administration.

It shouldn’t be necessary to say so. But some of today’s activists have a rigidly monolithic view of power. Among the many scathing open letters released by current and former employees of major cultural institutions, one particularly inflammatory one demands that the institutions in question dismantle the “systematic oppression” that they “readily participate in” and “acknowledge your participation in this systematic oppression.” They are to make amends through the “immediate removal” of their own leadership, a promise to “terminate immediately” any employee “caught” engaging in “any racially charged activities,” and so forth.

Last week, Public Seminar carried a response to a letter from faculty and staff of Princeton University that was far less strident yet included among its endless list of demands the creation of a faculty-only committee empowered to “oversee the investigation and discipline of racist behaviors, incidents, research, and publication on the part of faculty.” That would certainly make a professor think twice before expressing a heterodox opinion.

The Black Lives Matter movement has already registered an astonishing success. A recent New York Times poll found that a majority of Americans, including a majority of white people, regard the death of George Floyd as evidence of systematic police abuse of African Americans.

Lasting change can be built on such an epochal shift in public sentiment. It would be a disaster if the righteous anger that has filled America’s streets with protest dissipated itself in crusades against micro-aggressions and Instagram posts and mistakes of nomenclature and even spirited criticism and disagreements.

The protests of the sixties forced Americans to question pieties about the treatment of the disadvantaged at home and the use of power abroad. But an intolerant and self-righteous spirit also provoked a backlash that put an end to the hopes for reform embodied in the Great Society. Let us learn from that experience, and protect what needs to be protected, even as we change what needs to be changed.

James Traub is writing a biography of Hubert Humphrey.