AS PRESIDENT, Donald Trump decried critical race theory (CRT) as “toxic propaganda” that would “destroy our country”. In recent months Republican lawmakers have introduced several bills at the state and federal levels to curb its teaching in public schools. Among Americans who think they have a good idea of what CRT is, a majority think unfavourably of it. What is critical race theory, and why has it become a battleground of America’s culture wars?

The school of thought first emerged in universities in the 1970s from a perception that the advances of the civil-rights era had stalled. A group of black legal theorists, including Derrick Bell, Kimberlé Crenshaw and Patricia Williams, found academia’s understanding of race in America wanting. They shared a view that racism is pervasive. It is not principally a matter of personal belief; instead, they argued, it is structurally embedded in American institutions. Any honest effort to eradicate racism has to involve changing how institutions function. Simply ending segregation and outlawing overtly racist policies is not enough.

CRT has since spread from legal theory to influence all sorts of academic disciplines. It is not a fixed set of ideas. Instead, it seeks to examine how race and racism function in society. Though there are significant differences between scholars who claim the mantle, some common themes emerge. One thesis, common outside CRT circles, is that concepts of “race” are not grounded in science but rather defined (often cynically) by people. Another, championed by Mr Bell, is that steps toward racial equality are made only when they coincide with the interests of those in power, usually whites. Ms Crenshaw introduced the notion of “intersectionality”, which observes that people are members of multiple, intersecting groups and argues that viewing them as a member of only one risks ignoring important differences between people (for instance, black women experience discrimination differently than white women). But even these positions are up for debate among CRT theorists.

That fluidity, combined with the fact that CRT is not a movement with a specific platform but an approach to examining society, makes misrepresentation and caricature easy. The popularity of polemical bestsellers influenced by CRT, such as Robin DiAngelo’s “White Fragility”, and the debates on social media that they have spawned, raised CRT’s profile and made it a target. Some politicians and activists mistake CRT’s claim that American institutions benefit white people at the expense of others as meaning that white people are intrinsically racist. Ted Cruz, a Republican senator from Texas, decried the theory as being “every bit as racist as the Klansmen in white sheets.” In the past seven months Fox News, a right wing cable-news network, mentioned CRT more than two and a half times as often as CNN and MSNBC, two more liberal rivals, combined.

Critical race theorists can be prone to simplification and exaggeration, and CRT’s focus on group dynamics overlooks the still-crucial role of individual behaviour. Yet it is hard to imagine how a modestly popular academic view could destroy a country’s fabric. In fact, the instinct to ban the teaching of views thought objectionable may be the greater threat.

Dig deeper:Enlightenment liberalism is losing ground in the debate about raceJason Stanley on critical race theory and why it mattersJohn McWhorter on how critical race theory poorly serves its intended beneficiaries