政治技巧和个性是最重要的因素，这使得约瑟夫·斯大林成为苏联唯一的领导人。正如著名历史学家j。n。韦斯特伍德所说列宁的行为很狡猾，他写了一些关于他的有趣的东西，他过去常常看到他的对手在挖自己的坟墓，而他自己却常常袖手旁观。他把他比作一只偷骨头的狗，而另外两只狗正在争夺骨头。关于斯大林的这些信息是绝对正确的，因为这和他在政治权力斗争中所做的完全一样。首先，斯大林从左翼清除了他的对手，然后在1928年底从右翼清除了他的对手。前政治局委员尼古拉·布哈林(Nikolai Bukharin)也同意其他人对斯大林本性的看法，认为他冷酷无情。尼古拉·布哈林(Nikolai Bukharin)甚至在他的书中写道，斯大林是成吉思汗(Genghis Khan)，一个不择手段的阴谋者，为了维护权力可以牺牲一切。尼古拉·布哈林是那种经常改变理论的人，这取决于他下一步想除掉谁。
斯大林凭借政治技巧和人格在托洛茨基身上获得的巨大权力地位可以被视为最明显的优势之一(Sebag Montefiore, 2004)。历史学家克里斯•沃德(Chris Ward)写道:“斯大林的个性无法脱离他所处的世界。”在布尔什维克的指挥下，斯大林被任命为工农督察团团长。虽然他是政治局的新成员，但最近，他是主要的权力机构。1919年3月，雅科夫·斯维尔德洛夫死于西班牙流感，当时列宁身边只剩下几位高级官员，他可以和他们竞争，以取代雅科夫·斯维尔德洛夫。斯大林和列宁关系很好，也获得了列宁的信任。斯大林对列宁非常忠诚，列宁非常清楚，权力不应该掌握在自己手中。
Political skills and personality were the most important factors, which made Joseph Stalin the sole leader of the Soviet Union. As argued by a famous historian J.N. Westwood that Lenin was of cunning behaviour and he wrote something interesting about him that he used to see his rivals digging their own graves and he himself used to just stand back. He compared him to a dog that steals a bone while two other dogs are fighting over it. This information about Stalin was absolutely correct because it was exactly the same what he did during the struggle for political power. First, Stalin eliminated his opponents from the left and after that eliminated his opponents from the right by the end of the year 1928. Nikolai Bukharin who was a former member of Politburo also agreed with others about the nature of Stalin that he was ruthless. Nikolai Bukharin even wrote in his book that, Stalin is a Genghis Khan, an unscrupulous intriguer, who for the preservation of power could sacrifice everything. Nikolai Bukharin was that kind of a person who used to make a change in theories depending on whom he wanted to get rid of next.
However, one fact is very much clear about the political personality of Stalin is that, he played a crucial role in the history of the struggle for political power. An opponent of Stalin, Bukharin was a former contender in the battle of political power has his own views and therefore, one can conclude that his historical fact may be biased. Theodore Von Laue does not agrees with the major views and writes that “What he (Stalin) lacked were the very qualities in which the former exiles excelled.” From the facts of any trusted historians, one can easily disapprove with the points of Theodore Von Laue. For the downfall of Trotsky, the most important reason was the political skills of Stalin.
The immense position of power gained with political skills and personality of Stalin over Trotsky can be regarded as one of the most obvious advantages (Sebag Montefiore, 2004). Chris Ward, a historian writes, “Stalin’s personality cannot be divorced from the world in which he functioned”. Under the command of Orgburo, Stalin was appointed as the head of Workers and Peasants Inspectorate. Although he was the new member of the Politburo, lately, he was the main organ of power. When Yakov Sverdlov died of Spanish Flu in March 1919 there were a few top administrators left with Lenin with whom he could compete in order to replace Yakov Sverdlov. Stalin had good relations with Lenin and was able to gain his trust as well. Stalin was quite loyal to Lenin and it was very much clear in the mind of Lenin that the power should not be in one’s hand.