Stalin used his position within the party to cause Trotsky to lose support, thus isolating him in the party. Even though he was able to do this with ease, Trotsky’s fall had a lot to do with luck and timing as well. His support base was limited to the army, he seemed to be disconnected from the party most of the time which was a result of his disinterest in day to day politics and his ill health. Furthermore, he was eager to spread communism around the world by means of war, an idea that were unsettling to the Russians who were still recovering from the devastations of WW1. By 1923 he had been fairly isolated within the party and his proposition for an army attack on the government led to his condemnation on the 13th party conference.
Lenin’s Testement released after his death could have posed as a serious problem for Stalin if the party had taking heed of what Lenin had said. the death did bring Stalin his share of difficulties: Lenin's Testament, with its warning against Stalin and suggestion that he be removed from leadership, was read at the next Central Committee meeting. This was a critical moment: if his rivals had demanded compliance with the testament at this point, Stalin would not have survived their attacks--his support base was not yet large enough. However, Trotsky kept silent and Stalin's allies, Kamenev and Zinoviev, came to his defense. When they read out the testament they made it seem as if Stalin is now a better person because of Lenin’s leadership and productive critisicm was all the testemant was meant to be. Stalin recognized the fact that he was not the only one condemned in the testament and was therefore able to convince other victims of the testament to avoid taking Lenin’s words to seriously.
The following year, 1924, marks the beginning of Stalin's rise to power. At that point he was one of seven members of the Politburo--the others were Zinoviev and Kamenev, Trotsky, Nikolai Bukharin, Alexei Rykov, and Mikhail Tomsky. By 1930, Stalin would overshadow them, and by 1940 outlive them. His amazing success can be attributed to a combination of his own political genius and the mistakes that his rivals persisted in making. Stalin was gravitating toward the other three members of the Politburo--Bukharin, Rykov and Tomsky. These three formed a so-called "Rightist" bloc, differing on economic policy from Zinoviev and Kamenev. The "Rightists" wanted to continue with Lenin's New Economic Policy, which allowed considerable economic freedom for the peasantry. In 1924, the "Leftists" appeared to hold control over the Central Committee. But by the following year, Zinoviev and Kamenev realized that Stalin, whom they had saved from political ruin after Lenin's death, was betraying them and moving toward an alliance with Bukharin's faction. While Trotsky, the weakest member of the Politburo, remained aloof, the Rightists and Leftists clashed at the 1925 Party Congress, and the Rightists carried the day, despite vituperative attacks on Stalin and his "Socialism in One Country" by Kamenev. By the time of the next Party Congress, in October of 1926, Zinoviev and Kamenev had been removed from the Politburo, and Stalin felt secure enough in his power to urge the Party's official repudiation of their views as "anti-Leninist." Trotsky resisted, and in 1927 he was expelled from the party and exiled to Central Asia. Stalin was triumphant--now, even his ally in this struggle, Bukharin, grew nervous, as he realized that Stalin's power in the Party now overshadowed even his own influence.
By 1928, meanwhile, Bukharin was sufficiently alarmed over Stalin's growing power to seek reconciliation with the disgraced "Leftist", Kamenev. His efforts were fruitless, however--Kamenev was convinced that his only hope of survival lay in going along with Stalin, who was now beginning his campaign against the "Rightists." Having defeated Trotsky, Kamenev, and Zinoviev, he now readmitted the latter two into the Party and began to co-opt their ideas, pushing for immediate collectivization of land and rapid, state-controlled industrialization, as opposed to the more gradualist approach backed by Bukharin, Rykov, and Tomsky. Throughout 1928 and 1929, Stalin gathered support in the Central Committee, and by November 1929, he was powerful enough to have Bukharin removed from the Politburo.
Stalin has been viewed as a grey blur by most historians up until his rise to power in 1929. This is largely because he never made his intentions of becoming Russia’s next leader clear to anyone. He remained in the background and built momentum from there. This made it easier for him to make use of his political and manipulative skills in a political arena where leading party members did not consider him to be a significant threat. He dealt with obstacles neatly and never took his luck in certain steps in his rise to power for granted.