The Soviet Union experienced two very pronounced changes of direction in 1921 and 1929. At the beginning of the decade, the strategy of «War Communism» was abandoned, substituted by the completely different «New Economic Policy» (NEP); and changed again, at the end of those years, towards a strategy of forced industrialization based on the collectivisation of the agricultural sector. In recent years, some specialists have argued that this second change was unnecessary: i.e., rapid industrialization could have been achieved within the framework of NEP and the Law of Value. The purpose of this paper is to argue, from a theoretical point of view, and with the help of the model that best summarizes the strategy of rapid industrialization, that this new interpretation cannot be sustained, and that those authors that defended the incompatibility of NEP and rapid industrialization were correct.