after three years of participation in world war i, the economy of the russian empire was in crisis. in march 1917 the so-called february revolution overthrew the regime of tsar nikolai ii and replaced it with a fledgling constitutional democracy headed by a succession of leaders ending with alexander kerensky. the economy remained disrupted and russia failed to disengage from the bloody european war, and on november 7, 1917 the kerensky government fell in a second revolution, this time led by the bolshevik party of revolutionary socialist vladimir ulyanov (lenin).