Stalin's defeat of his political rivals 1924 - 1929

Why was Stalin able to defeat his political rivals so easily in the years 1924-1929?

Take into consideration - 

• Powerbases
• Personalities
• Lenin's testaments
• Ideology
• Lenin's funeral

Powerbases of the contenders

• Stalin was General Secretary of the Bolshevik party at the time of Lenin's death. He had the power to promote and demote members of the party and therefore used his position to gain support. He was also in charge of the Lenin enrolment, so young members that were enrolled looked up to him and supported him. 
• Kamenev was acting chair of the Sovnarkom during Lenin's illness, was the chairman of the central committee, could elect members of the Politburo AND was the head of the Moscow branch of the Communist party - but he failed to earn the respect of the Moscow party. 
• Zinoviev seemed to be fairly disliked in the party or at least subject to the party members' indifference. 
• Bukharin was the favoured contender and was thought to be the 'eventual successor of Lenin' prior to Lenin's death. Lenin saw him as a 'golden boy' and everybody thought that he'd eventually govern the USSR.
• Young communists supported Trotsky, as did the Red Army. They were very loyal to him. He was, however, seen as 'too Western' and it was thought that he was 'Bonapartist'. 

Personalities of the contenders

• Stalin seen as…