Everything must justify its existence before the judgment seat of Reason, or give up existence.
The proletariat uses the State not in the interests of freedom but in order to hold down its adversaries, and as soon as it becomes possible to speak of freedom the State as such ceases to exist.
The state is nothing but an instrument of opression of one class by another - no less so in a democratic republic than in a monarchy.
All history has been a history of class struggles between dominated classes at various stages of social development.
Look at the Paris Commune. That was the Dictatorship of the Proletariat.
Just as Darwin discovered the law of development of organic nature, so Marx discovered the law of development of human history: the simple fact, hitherto concealed by an overgrowth of ideology, that mankind must first of all eat, drink, have shelter and clothing, before it can pursue politics, science, art, religion, etc.