Marx explains this question most thoroughly in his Critique of the Gotha Programme (letter to Bracke, 5 May 1875, which was not published until 1891 when it was printed in Neue Zeit, vol. IX, 1, and which has appeared in Russian in a special edition). The polemical part of this remarkable work, which contains a criticism of Lassalleanism, has, so to speak, overshadowed its positive part, namely, the analysis of the connection between the development of communism and the withering away of the state.