“And I still think that the work in which I am engaged now, despite its extremely insufficient and fragmentary nature, is the most important work of my life—more important than 1917, more important than the period of the Civil War or any other.
“For the sake of clarity, I would put it this way. Had I not been present in 1917 in Petersburg, the October Revolution would still have taken place—on the condition that Lenin was present and in command. If neither Lenin nor I had been present in Petersburg, there would have been no October Revolution: the leadership of the Bolshevik Party would have prevented it from occurring—of this I have not the slightest doubt! If Lenin had not been in Petersburg, I doubt whether I could have managed to conquer the resistance of the Bolshevik leaders. The struggle with ‘Trotskyism’ (i.e. with the proletarian revolution) would have commenced in May 1917, and the outcome of the revolution would have been in question.
“But I repeat, granted the presence of Lenin the October Revolution would have been victorious anyway. The same could by and large be said of the Civil War, although in its first period, especially at the time of the fall of Simbirsk and Kazan, Lenin wavered and was beset by doubts. But this was undoubtedly a passing mood which he probably never even admitted to anyone but me.
“Thus I cannot speak of the ‘indispensability’ of my work, even about the period from 1917 to 1921. But now my work is ‘indispensable’ in the full sense of the word. There is no arrogance in this claim at all. The collapse of the two Internationals has posed a problem which none of the leaders of these Internationals is at all equipped to solve. The vicissitudes of my personal fate have confronted me with this problem and armed me with important experience in dealing with it.
“There is now no one except me to carry out the mission of arming a new generation with the revolutionary method over the heads of the leaders of the Second and Third International. And I am in complete agreement with Lenin (or rather Turgenev) that the worst vice is to be more than fifty-five years old! I need at least about five more years of uninterrupted work to ensure the succession.”
Trotsky’s Diary in Exile — 1935



