Uneven and Combined Development uniquely incorporated societal multiplicity into Marxist theory. So why did its first application end in Stalinist dictatorship? This paper seeks an answer by turning the idea back on itself, applying it first to Trotsky’s doctrine of ‘permanent revolution’ and then to Marx’s original idea of revolution. Trotsky hoped that Russia’s ‘revolution of backwardness’ would be rescued by ‘advanced’ revolutions in the West, modelled on the French revolution. But what if – as this paper argues – that event too was ultimately a ‘revolution of backwardness’? Two implications follow. First, Trotsky’s ‘permanentist’ strategy was logically flawed: if all modern revolutions have been internationally-generated catch-up revolutions, then the idea of Bolshevism being rescued by ‘advanced revolutions’ elsewhere fails. But second, the consequences of multiplicity reach even deeper than Trotsky realized: they underlie and explain the original political formation, and troubled history, of revolutionary Marxism itself.