in from the beginning. Knowing they had the "right stuff" (because they won), we look for it when we examine them, and look for the lack of it when we examine the Mensheviks. But the confusion of present day Russia reminds us that the Bolsheviks may, just, have happened to be in the right place at the right time.
Granting that note of caution, it is fair to say that the Bolsheviks are widely perceived as having enjoyed fundamental advantages in ideology, organization, and personnel that contributed to their success in competition with the Mensheviks and the other factions that struggled for control of the Russian Empire during 1917. All of these theories are actually interrelated. Thus, the simplest explanation for the success of the Bolsheviks is that they had the extraordinary personality of V.I. Lenin leading their movement through its years of development, and returning to take command in the critical weeks of summer, 1917. Whatever movement was led by Lenin, it could be argued, enjoyed the greatest prospect of success.
But this simple explanation is not isolated from those explanations that look for deeper underlying causes. Lenin, after all, did not choose to become a Bolshevik at random. He was drawn to Bolshevism, among all the radical or revolutionary alternatives available to him, by certain qualities he felt in the movement's ideology or followers. He in turn shaped that ideology and the character of the followers who joined the movement under his leadership into his own mold. At the very least, in the Lenin centered view, we can say that the Bolshevik party was the one that attracted Lenin, and which he made his own.
Alternatively, we can argue that the Bolsheviks won because the nature of its ideology and program were such that it would have created a Lenin if one did not exist. After all, Lenin was far from the only commanding personality among the Bolsheviks, even if he stands o...