Anyone who thinks history follows a dialectical logic should study world history with the so-called macro model. The dialectic is not present as a dynamic. The dynamic is entirely logical and follows the simplest kind of aristotelian yes/no logic.
The real logic of history is a concealed variant of ‘evolutionary’ sequencing in a fashion that resembles ‘punctuated equilibrium’. The latter term can produce confusion, so we can point to the way that ‘transitional’ periods induce form of evolutionary or developmental transformation and then settle into something like equilibrium.
In any case, the left needs to adopt a postdarwinian stance as soon as possible. Without any nonsense about dialectics here. The fantasy that Marx’s dialectic yields some insight into evolution is simply nonsense.
Marx had it right the first time: his insight that darwinism smacked of English economic ideology was filtered out of later discussion on the left.