Stalin was enormously popular, which actually became a problem for him after World War II. From Anna Louise Strong's This Soviet World, written in 1936:

The operation of Soviet democracy is thus so intimate, continuous and organic that the observer fresh from capitalist politics hardly recognizes it as government. Where is the debate? Who determines general policies? Can the people throw out the upper officials? Can they throw out Stalin? The Communist Party? The Soviet voter, when asked these last questions, replies in a puzzled way: “Why should we want to?” The questioner thinks he has been evaded. But all elections presuppose an existing economic system, which voting is powerless to change. Voters in America cannot change Rockefeller’s method of operating oil companies for private profit. Similarly no Soviet election raises the issue of returning public properties to private hands: this was settled by the Revolution, and forms the foundation beneath the whole government.

Barring that question, there is nothing whatever that Soviet voters cannot change. They actually do change thousands of officials at every election, and as their acquaintance with the wider problems of the country grows, the forms of democracy are being widened to include direct control of the highest officials. Stalin’s chief post is not in the government, but as general secretary of the Communist Party, which would certainly remove him if his policy and actions should ever discredit him with the people; at present he is by far the most popular man in the country. To throw out the Communist Party bodily would be to throw out all the leading and organizing elements in all factories, farms, schools and enterprises; it could clearly be done only by upheaval leading to chaos. But the citizens are constantly at work changing the very membership of the Party, any member of which may be “cleaned out” on protest of his non-Party associates that he is too dictatorial, too rough towards workers, or merely not a fit leader.[27]