Under Stalin structure remained largely the same with the power concentrated in the Politburo
The 1936 constitution led to a structural change in government but not in the centre of power. There was now an elected supreme soviet and Presidium, from which the council of Ministers was elected
The new chair of the presidium (president of the USSR) was solely a figure head position. On paper it looked democratic, but it was adopted at the height of Stalinist purges and there was only one candidate to vote for in each constituency