This article is devoted to the problem of the legitimacy of revolution in general and of the Russian revolution of 1917 in particular. The problem of legitimacy of revolutions may be divided into two components: first, the legitimacy of anti-government protests; and secondly, the legitimacy of the new revolutionary government. The second point divides society into uncompromising camps, which happened to the government of the Jacobins in the French Revolution and to the government of Bolsheviks after Russia’s October Revolution — and still divides Russian society today. The Russian revolution of 1917, in its February and October segments, based its legitimacy — as had all its predecessors — on the existing legislature and on the right of force. The particular feature of the Russian Revolution was that the extreme left, represented by the Bolsheviks, was able, unlike the Jacobins, to retain power thanks to sufficient societal support. Thus they were able to win the civil war, first, and secondly, to take over a society that was exhausted after a prolonged period of disorder and which, in its majority, was eager for peace — and therefore either accepted the new power or was prepared to tolderate it.