tldr: Martov argues that, contrary to Lenin's interpretation, Marx and Engels saw the democratic republic—not soviets—as the essential and specific political form through which the proletariat could achieve and exercise its dictatorship, transforming the state into a truly democratic instrument of class rule.
https://www.marxists.org/archive/martov/1921/xx/decomp.htm
>Psychologically the most characteristic thing about the rush of the “extreme leftists” toward “sovietism” is their desire to jump over the historic inertia of the masses. Dominating their logic, however, is the idea that soviets constitute a new, “finally discovered,” political mode. This, they say, is the specific instrument of the class rule of the proletariat, just as the democratic republic is according to them the specific instrument of the rule of the bourgeoisie.The Communist Manifesto declared: “We have already seen that the first step in the working-class revolution is raising the proletariat to the position of a ruling class, the conquest of democracy.”
In 1852, in Eighteenth Brumaire, Marx wrote:
Every previous revolution has brought the machinery of State to a greater perfection instead of breaking it up.On the 12th of April 1871, in a letter to Kugelmann, he formulated his viewpoint on the problem of revolution as follows:
If you look at the last chapter of my Eighteenth Brumaire, you will see that I declare the next attempt of the French Revolution to be not merely to hand over, from one set to another, the bureaucratic and military machine, as was the case up to now, but to shatter it. That is precisely the preliminary condition of any real people’s revolution on the Continent. It is exactly this that constitutes the attempt of our heroic Parisian comrades.It is not for any idle reason that Engels wrote in 1891, in his preface to Civil War in France:
<… the State is nothing more than a machine for the oppression of one class by another, and indeed in the democratic republic no less than in the monarchy; and at best an evil inherited by the proletariat after its victorious struggle for class supremacy whose worse sides the proletariat, just like the Commune, will have at the earliest possible moment to lop off, until such time as aPost too long. Click here to view the full text.