‘Whenever anyone dares mention the insensitivity of promoting speakers whose invitation risks legitimising such social ills as prejudice, racism or rape,’ wrote Conrad Landin in The Guardian in 2013, ‘the same defence is given: free speech.’ The journalist and activist was objecting to a controversial offer extended to France’s Right-wing Marine Le Pen to address the Cambridge University debating society.

Within university walls, but also far beyond them, it’s an old controversy. The debate’s protagonists, to be sure, have changed over time. For centuries, censorship was the preserve of the reactionary forces of monarchy, aristocracy and church. The threat posed by free speech was to monopolies of power. (In much of the world today, it still is.) Liberalism battled them.

Enter Karl Marx, stage left. Marxism turned that traditional role of liberalism on its head. Having once been viewed as the decisive force against elite power, liberalism now became the fiercest elitism of all. Capitalism’s class divisions, for Marx, had only replaced old elites with new ones. The latter became legitimated through a mythology – a sheer ideology – of universal freedom and equality. Since the mid-20th century, that view has guided radical critiques of free speech even when Marxist doctrine is not directly cited. Within more extreme circles on both Right and Left, liberalism becomes cast not as the vanguard against the political establishment but as its creeping embodiment.

The myth of universal, individual freedom, on that view, masquerades as a bulwark against that selfsame totality of power that it, in fact, comes to absorb. Unhindered public discourse becomes not freedom’s sanctuary but its enemy. It serves not to promote marginal voices but to keep them marginal. Madame Le Pen’s Cambridge debut caters not to the critical scrutiny of established power relations, but to their mindless perpetuation.

The main schism in today’s free speech debates pits liberals, advocating unbridled speech as a tool of freedom, against radicals, who unmask unbridled speech as a tool of class privilege. But that rift tells only one story. In almost all democracies today (the United States being the sole and oft-criticised exception), mainline liberal doctrines overwhelmingly require limits on provocative speech. Liberals today largely consent to drawing lines between the lawful and the unlawful expression of ideas. They disagree only about where that boundary should lie. Indeed, an ever more distinct libertarianism has arisen in diametric opposition to the ‘balance of interests’ approaches of our more conventional liberal approaches. The strident (though still minority) libertarian would wholly abolish those lines in favour of free speech. Accordingly, far from dissenting from the more mainstream liberal line-drawing, radicals wish merely to draw the lines more tightly around certain types of expression. They differ from liberals only as a matter of degree, not as a matter of principle, even when they appear to adopt different philosophies or vocabularies.

Most liberals are willing, then, to draw the lines that limit speech. Meanwhile, some formidable radicals are not. Marx might well deconstruct liberalism’s universalist pretences, unmasking it as its opposite, namely, as a strategy of class entrenchment and exclusion; yet Hegel had already deconstructed that same liberal aspiration more optimistically: the ancien régime overcomes the illusion of formal equality by instilling within liberals an ingenuity sharper than that of the complacent power structure of the old aristocracy. So runs the famous master-servant dialectic. It tacitly re-surfaces in Excitable Speech (1997), an exercise in the leftist-critique-of-leftism by Judith Butler (whose early career had indeed focused on Hegel). While the dominant radicalism condemns hate speech as an active construction and entrenchment of socio-politically disempowered group identities, Butler views such seemingly repressive acts as spurs for those groups’ political awareness and mobilisation.

I have no wish to pull contemporary critical theory down from its heights. However, despite the Hegelian salad topped with post-modern sauce, one would struggle mightily to identify a single element in Butler’s thesis not wholly compatible with the justifications for free speech adduced in Chapter 2 of John Stuart Mill’s On Liberty (1869), that stodgy old stalwart of Anglo-American liberalism. Indeed, notwithstanding Marx’s bitingly anti-liberal campaigns, even he gazes suspiciously upon censorship.

A tradition as old as Mill’s, renewed by Louis Brandeis, had coupled the efficiency of free speech to that of free markets. The remedy for any bad product of markets, on that view, is more and better products. And the remedy for bad speech is ‘more speech’. For leftists, that coupling of free speech with free markets ends up too true by half. Marketplaces of goods serve not to overcome class divisions but to seal and to legitimate them as inevitable products of the necessary forces of ‘natural’ competition. The ‘marketplace of ideas’ does the same. It guarantees a vacuously formal equality of access to all, but is in fact always systemically skewed towards wealthy and powerful voices, against the subordinated ones.

Six years after Butler’s tract, however, Raoul Vaneigem, veteran exponent of Francophone post-Marxism, performed a similar act of arch-leftist rebuttal to core leftist nostrums. While liberalism couples the marketplaces of goods and of ideas to argue against regulation, and radical critique couples them in favour of it, Vaneigem’s strategy is utterly to de-couple them. In Rien n’est sacré, tout peut se dire (2003), the situationist philosopher argues that unbridled speech, far from straightforwardly recapitulating the commodified uniformity of neo-liberal market forces, is the best weapon for de-stabilising them. Unlike the pseudo-freedom of the market, public discourse is a genuine freedom – the freedom of creative de-stabilisation of established, elitist power. (Jacques Rancière and Slavoj Žižek endorse similar views of citizen-based democracy.)

If we want to avoid the impasses and repetitions plaguing the free-speech debates, one way is to stop assuming that ‘the liberal position’ always dictates one outcome, and ‘the radical position’ another. Both approaches supply plausible justifications for supporting restrictions on public discourse – but even stronger grounds for opposing them.