Original sentence: Despite his formal position being originally without significant influence, and his office being nominally but one of several Central Committee Secretariats, Stalin's hard work in the Party from 1928  onwards led to him becoming the chosen party head and the leader of his country
Edited sentence: Despite his formal position being originally without significant influence, and his office being nominally but one of several Central Committee Secretariats, Stalin's increasing control of the Party from 1928  onwards led to him becoming the de facto party leader and the dictator of his country