"The history of a revolution is for us first of all the history of the forcible entrance of the masses into the realm of rulership over their own destiny."
This memorable sentence appears in Leon Trotsky's classic work, The History of the Russian Revolution. It contains the essential measure - revolution from below - that socialists must use to distinguish the revolutions we can applaud from those we cannot.
The dramatic events in Nepal last month were an inspiring example of a revolution we can applaud. For here was a revolutionary situation marked first and foremost by the courageous determination of the Nepalese masses to take history by the scruff of the neck and force it onto a path of their own making.
Despite the brutal shoot to kill policies of King Gyanendra, Nepal's workers led the way by enthusiastically answering the opposition's call for a general strike. The strike's success gave heart to many hundreds of thousands who then defied curfews and took to the streets of Kathmandu. Again and again, their howl of anger at abject poverty and semi-feudal authoritarian rule was to force the pace of events, prompting one BBC journalist to wonder if the opposition would be able to control the spectre it had summoned from the depths of Nepalese society.
This was not the only expression of concern. India feared for its troubled northern provinces. China feared for Tibet. The US feared the loss of a royal recruit to its "war on terror". Here was a revolution, then, with the potential to put a seditious spanner in the works of three imperialist powers.
However, some revolutions cannot be read so easily. Despite appearances to the contrary, Ukraine's so called Orange Revolution of 2004 showed none of the defining characteristics we associate with a true revolution.
In fact, here was a "revolution" in which the crowds who took to the streets and squares of Kiev to support the pro-US presidential candidate, Viktor Yushchenko, never became the key driving force behind events in the way the Nepalese people have. With Washington and Moscow siphoning enormous sums to the campaigns of their chosen candidates, the Orange Revolution instead took on the air of a well controlled and orchestrated affair in which the pace of events was set exclusively from above by the manoeuvrings of the rival presidential candidates and their imperialist sponsors.
This was a "revolution" bereft of wider anti-imperialist implications which the US subsidised and exploited for its own ends. In short, it was a "revolution" in which the masses never took control of their own destiny.
Socialists applaud revolutions in which the masses are the driving force behind events, even if those revolutions have limited democratic aims, such as in Nepal. We do so not just because it is hard evidence for our contention that the masses have both the intelligence and the power to make their own history, but also because a revolution forged from below has the potential to grow into one altogether more radical.
In February 1917, a democratic revolution powered from below broke out in Russia. By October, that revolution had ripened into a socialist one. Without a mass movement from below driving events forward, Lenin, Trotsky and the Bolsheviks could never have led the working class to power. When they did, every imperialist across the globe had reason to take fright.