Karl Marx, answered from the texts and cited to the page.
The dictatorship of the proletariat is not a state-bureaucratic apparatus standing above society in the bourgeois manner — it is the political form at last discovered for the emancipation of labor, and that form was found in the Paris Commune of 1871: the working class organized as the ruling class, smashing the centralized state machinery and replacing it with the self-administration of producers.
The Commune is the dictatorship of the proletariat in its actual historical realization. There is no contradiction between anti-statist self-administration and class power, because the working class in power dissolves the state-form as a separate apparatus standing over society — the proletariat "abolishes itself as proletariat" by abolishing the conditions that produced it.
The transition is real, the class character of the transition state is real, the supersession of the bourgeois state-form is real, and these are one movement.12
The very existence of the Commune involved, as a matter of course, local municipal liberty, but no longer as a check upon th^ now superseded State power.The Civil War in France, pp. 78–79
Amidst all these horrors, Thiers, forgetful of his parliamentary laments on the terrible responsibility weighing down his dwarfish shoulders, boasts in his bulletins that VAssemhlee siege paisiblement (the Assembly continues meeting in peace), and proves by his constant carousals, now with Decembrist generals, now with German princes, that his digestion is not troubled in the least, not even by the ghosts of Lecomte…The Civil War in France, p. 70
The most politically-charged contested position. Lenin's State and Revolution (1917) presented the dictatorship of the proletariat as a transitional state held by the vanguard party — a reading the texts can support but that the Commune-praising material in Civil War in France pulls against. Hal Draper's four-volume Theory of Revolution is the most thorough textual reconstruction. Stedman Jones emphasizes the anti-statist Commune material as central to Marx's actual position. The Bakuninist anarchist critique (any state is the betrayal of revolution) has its mirror in the Marxism-Leninist defense (the state is necessary for class transition).