This type of criticism was revived on the left of the Russian Communist Party after the 10th Congress in 1921, which introduced the New Economic Policy (NEP). Many members of the Workers' Opposition and the Decists (both later banned) and two new underground left communist groups, Gavril Myasnikov's Workers' Group and the Workers' Truth group, developed the idea that Russia was becoming a state capitalist society governed by a new bureaucratic class. The most developed version of this idea was in a 1931 booklet by Myasnikov.