We live in strange political times. But one of the strangest recent developments has been the rise of racial thinking on the left, historically the progenitor of equality legislation and defender of minorities. And no, for once, this isn’t a piece about anti-semitism in Labour.

The new Prime Minister Boris Johnson’s appointment of more ethnic minorities than ever to the top of government—including Sajid Javid as Chancellor of the Exchequer and Priti Patel as Home Secretary—has caused a meltdown among certain sections of the left. To be fair, Ed Miliband-biographer Mehdi Hassan struck a welcoming note: “Even if you loathe them & their politics … it matters to young UK Asians to have a chancellor called Javid & a Home Sec called Patel.” But he has, as it were, been in the minority.

Replying on Twitter to James Cleverly, now Conservative Party Chairman, the Labour shadow minister Clive Lewis wrote: “you & other black members of that cabinet had to sell your souls & self-respect to get there.” He didn’t use the phrase Uncle Tom, but it seemed on the tip of his tongue. Pop-up Corbynista Ash Sarkar said she would never call the ministers Uncle Toms because the character, “refuses to whip his fellow slaves.”

The assumption that black and Asian people somehow organically share the same views and that any deviators from the correct line are not full members of their group—in the words of Canary editor Kerry-Ann Mendoza, “no longer a person of colour”—is closer to essentialist racism than any of the indefensible phrases Johnson has used in his Telegraph columns. So why is this happening? And what are the intellectual roots of the left’s attempts to fix group identity?

One answer can be found in a 1985 article by the postcolonial theorist Gayatri Chakravovty Spivak—clever, but perhaps too clever for some of those she’s influenced. It might seem a long way from the translator of Derrida’s Of Grammatology to today’s intemperate tweets. But half-remembered ideas picked up by humanities students often come to shape “the discourse” in influential ways. So stay with me.

In Spivak’s knotty essay, “Subaltern Studies: Deconstructing Historiography,” she focuses on the lives of the oppressed masses in India during colonial times. To what extent is it possible, she asks, to genuinely retrieve the lives of such individuals when the only records we have of them are mediated through the eyes of their British oppressors. Can the subaltern—a term borrowed from Gramsci—ever speak in her own voice? Spivak has her doubts: writing about Bengali peasants, for example, means inevitably making generalisations about their attitudes that will not apply in all circumstances. In other words, essentialising.

But even if the process of writing subaltern history flattens out complexity, the other option is keeping silent—and then who wins? Spivak identifies an alternative tactic in the work of the academic circle she is writing about known as the Subaltern Studies group, which sought to read the traces of a “rebel consciousness” through the writings of colonial officials. Spivak sees some value in their work but with a caveat: “I would read it, then, as a strategic use of a positivist essentialism in a scrupulously visible political interest.” So you can essentialise a group, if you do it for the right reasons. Crucially, you must remember that what you’re doing is not intellectually defensible, only politically; it should be a tactic, not a credo.

The idea of strategic essentialism (a term now disavowed by Spivak) has been hugely influential in postcolonial theory, and therefore on university activists seeking to fight racism and other kinds of discrimination. In the interests of unity, ethnic minorities have to stick together—like striking workers at a factory. But for every solid union official on the picket line, there will be someone who crosses it—a scab. What Javid and Patel are doing, say their critics, is scabbing on their race.

Factory workers or toilet cleaners share an economic interest, at least. But do people from South Asian backgrounds in Britain, for example, really have that much in common? One-third voted for Brexit. Among the East African Indian community from which Patel hails, social and economic conservatism is common—even dominant. South Asians are more likely to go to university than their white counterparts. No one should pretend that racism doesn’t exist—it does, and it matters. But the idea that Asians are some kind of subaltern class doesn’t apply in this case. The examples are too various.

Essentialising a group in the face of racial discrimination may in some cases, for example equality legislation, be a necessary evil. But it is an evil. Sections of the left have forgotten that it was always supposed to be strategic essentialism: you can’t actually believe that someone’s race defines their worldview, simply because that is…well, a bit racist.

There is a glimmer of light though. In taking Javid and Patel to task for their policies, the left is absolutely right. When Javid stripped British Isis supporter Shamima Begum of her citizenship, I was outraged. And yet I wonder if the Old Etonian middle-aged white man Rory Stewart, with his understanding of the complexity of the Middle East, would have made the same decision. Perhaps not. As always, the judgment of the individual is paramount—not their “identity,” or rather one visible facet of it. What people believe is more important than who they are. If the left, in a roundabout way, could come round to that position, just maybe it could find a way out of this mess.

Read an extract from Sameer Rahim’s novel Asghar and Zahra (JM Originals)