Kimberlé Crenshaw, a pioneering legal scholar who teaches at both U.C.L.A. and Columbia, has watched with alarm the attempts to suppress an entire intellectual movement. It was Crenshaw who came up with the name “critical race theory” when organizing a workshop in 1989. (She also coined the term “intersectionality.”) “The commitment to free speech seems to dissipate when the people who are being gagged are folks who are demanding racial justice,” she told me.

Many of the intellectual currents that would become critical race theory emerged in the 1970s out of disappointment with the incomplete work of the civil rights movement, and cohered among radical law professors in the 1980s.

The movement was ahead of its time; one of its central insights, that racism is structural rather than just a matter of interpersonal bigotry, is now conventional wisdom, at least on the left. It had concrete practical applications, leading, for example, to legal arguments that housing laws or employment criteria could be racist in practice even if they weren’t racist in intent.

Parts of the critical race theory tradition are in tension with liberalism, particularly when it comes to issues like free speech. Richard Delgado, a key figure in the movement, has argued that people should be able to sue those who utter racist slurs. Others have played a large role in crafting campus speech codes.

There’s plenty here for people committed to broad free speech protections to dispute. I’m persuaded by the essay Henry Louis Gates Jr. wrote in the 1990s challenging the movement’s stance on the first amendment. “To remove the very formation of our identities from the messy realm of contestation and debate is an elemental, not incidental, truncation of the ideal of public discourse,” he wrote.

Disagreeing with certain ideas, however, is very different from anathematizing the collective work of a host of paradigm-shifting thinkers. Gates’s article was effective because he took the scholarly work he engaged with seriously. “The critical race theorists must be credited with helping to reinvigorate the debate about freedom of expression; even if not ultimately persuaded to join them, the civil libertarian will be much further along for having listened to their arguments and examples,” he wrote.

But the right, for all its chest-beating about the value of entertaining dangerous notions, is rarely interested in debating the tenets of critical race theory. It wants to eradicate them from public institutions.

“Critical race theory is a grave threat to the American way of life,” Christopher Rufo, director of the Center on Wealth and Poverty at the Discovery Institute, a conservative think tank once known for pushing an updated form of creationism in public schools, wrote in January.