Our American Revolution and the words of Thomas Jefferson terrified the ancien régime. The blood of Parisian aristocrats ran in ditches dug for that purpose in the Place de la Concorde. After Edmund Burke's Reflections on the Revolution in France appeared, many apprehensive educated persons who formerly had harbored revolutionary thoughts launched a period of counter-revolution. Shelly was not one of them.
If read at all in today's public schools, Shelly is best known for Ode to the West Wind and Ozymandias. The latter, a sonnet, recounts a forgotten ruler's hubris and the fate of his empire.
Somewhere in man's psyche there must lie a solution between risking le terror and the social injustices of l'ancien régime. History teaches us the inevitability of the death of empires. If there exists a way to prevent the growth of empire, then there is no need to concern ourselves with preventing the death of empire.
Empire is a creature of those few who are driven to exercise power, financially and militarily, over others. How can the many, whose makeup does not oblige them to seek power over others thwart the machinations of the few who, seeking power, fame, and glory, lust after more?
We already have the answer! In his personal papers, contained in a 1798 draft of The Kentucky Resolutions, Thomas Jefferson wrote, ...in questions of power then, let no more be heard of confidence in man, but bind him down from mischief by the chains of the constitution....
Shelley's father-in-law, William Godwin, was revolutionary in espousing free love. However, when his sixteen year old daughter ran off with Shelley and they returned to England Godwin refused to speak to her. Revolutionary ideas too close to home may spark counter revolutionary tendencies.
Shelley was, in many ways, a thoroughly modern man. His revolutionary poem does have a very modern ring to it.