Why did stalin becom leader after lenin, not trotsky?

In the beginning, as Lenin end grew nearer, there were five potential leaders, Bukharin, Kamenev, Zinoviev, Trotsky and Stalin. It seemed so obvious that there only was one man to take over Lenin's reign - Trotsky. He was Lenin's right hand man, but a close second was Stalin. People saw him as the one who came second, that's all he was; there was no way that he would beat Trotsky in the race for leadership, but what they didn't know that Stalin's cunning would overtake then all and he would end up being the leader of Russia.

Stalin knew he would have to worry about the other three, as separate candidates. Trotsky was his main rival. Stalin made Lenin's funeral the centre stage for his plotting. First he tricked Trotsky into turning up to Lenin's funeral on a wrong later date. By not turning up, Trotsky's reputation was damaged.

The two major economic policy makers of the USSR, ...

Joseph Stalin, 1894

Stalin and Bukharin, c.1928

Stalin also used Lenin's funeral to make himself look better by organising the actually funeral, making it look like he should be the one to carry on Lenin's work.

Krupskaya gave Lenin's secret testament to the Central Committee, but Zinoviev and Kamenev didn't it let become public knowledge as not only did it show Stalin as a bad leader, but also Zinoviev and Kamenev didn't look too good in the testament. In addition, they didn't see Stalin as much of a threat and thought they could use him to help defeat Trotsky, who was seen as very good in Lenin's testament.

Zinoviev, Kamenev and Stalin were at the height of the race at the moment. At this moment Trotsky criticised the party calling it too bureaucratic and less democratic. In 1924, Zinoviev and Kamenev built up a ferocious campaign against Trotsky, which questioned...