When Lenin died on the 21st of January 1924 many thought that Trotsky was his natural successor as the leader of the Bolshevik party. However, even prior to Lenin's death, Stalin was building his power base, which ultimately would allow him lead the Bolshevik party.
In October 1927, Trotsky, Kamenev and Zinoviev were expelled from the Central Committee of the Bolshevik party of Soviet Russia. Under pressure from the Central Committee, Zinoviev and Kamenev agreed to sign contracts promising not to create conflict in the party by making speeches attacking official policies. Leon Trotsky refused to sign and was exiled to the Turkish island of Prinkipo.
On the 21st of December 1929 Stalin celebrated his 50th birthday as the absolute dictator of Soviet Russia.
How was Trotsky able to be backed by Lenin and considered by most Russians as the clear choice for the next leader after Lenin's death and still not become the leader of the party? Trotsky had substantial power. He was the commissar for war with a considerable level of respect. He was the hero of the civil war; he had a growing cult who had faith in him without question. However, this just fuelled his arrogance and he failed to even acknowledge the threat of Stalin.
I will go onto discuss the reasons and opinions behind one of histories greatest misfortunes.
Trotsky versus the Triumvirate
From 1921 until his death in 1924 Lenin suffered a series of strokes. However, he kept working until a major stroke made him mute in March 1923. In 1923 Trotsky then found himself up against Stalin, Zinoviev and Kamenev (the triumvirate) for the leadership. Trotsky was no longer fighting class enemies as he had been in the civil war. He was now fighting his own members of his party which for someone so devoted to his party and the cause must have been hard.
The triumvirate was an odd alliance in hindsight, as the trust between the three men was very misplaced. Zinoviev thought he was using Stalin to get into power. He was probably the most delusional of the triumvirate because he genuinely felt that he was going to be the next leader of the Bolshevik party. Kamenev was showing his support to his friend Zinoviev and the old Bolsheviks of the party, he just wanted to stop Trotsky, a new and ambitious member of the party, from becoming the leader over the older members who had been dedicated to the cause for longer. Stalin was actually using Zinoviev and Kamenev to defeat Trotsky. Trotsky describes Stalin as "The most eminent mediocrity in our party." John Reed, who recorded the October revolution in his book, "Ten Days That Shook the World", described Stalin as a "grey blur, looming up now and then dimly and not leaving a trace." Stalin was clearly underestimated by everyone.
In 1921 a pressure group within the party, calling itself the Workers' Opposition arose calling for trade union rights. Lenin implemented a policy condemning them. He then went further and succeeded in passing a resolution which...