Here is Marx himself describing the withering away of the state in chapter 2 of "The Communist Manifesto":
"When, in the course of development, class distinctions have disappeared, and all production has been concentrated in the hands of a vast association of the whole nation, the public power will lose its political character. Political power, properly so-called, is merely the organised power of one class for oppressing another. 2/6
@Radical_EgoCom the myth is that it was ever Communist. Communism has never been implemented in completeness. Modifications have always been made to take power from the people, whereas true Communism as originally formulated by Marx is a 100% direct democracy.
The USSR was implemented as Marx truly intended: overthrow of the bourgeois state, establishment of the dictatorship of the proletariat (i.e., socialism, or as Marx put it, the "lower stage of communism"), the gradual abolition of class (which the USSR obviously didn't achieve), and from that the gradual withering away of the state into what Marx called the "higher stage of communism," or just communism. 1/6