``I can't think of any artists who were progressive heads of state. John Wilkes Booth was a political "activist" of sorts.'' CB
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There was one example, but it is so ambivalent, that it might not count.
Jacques Louis David, served on the Committee for Public Safety with Robespierre and Saint-Just. He signed the execution order for Louis XVI as well as one for his former patron, Antoine Lavoisier.
David's principle political contributions were to design various revolutionary holidays under the new calendar that included Festival of the Supreme Being a religious holiday, and Days of Revolution, scripts and costumes featuring various classes and trades of the people, with everybody dressed up in ancient Roman and Greek costumes. He also did several revolutionary martyr icons (engravings based on his paintings) of Murat and Joseph Barra. The latter was a messanger boy for the revolutionary armies and was captured and killed. Really tear jerker stuff. Sons of the revolution and such. So David was the first great revolutionary propagandist and invented the basic tools of the trade.
When Robespierre and Saint-Just were arrested, David was put under house arrest to wait see if he was to face the implacable Madame Guillotine. He was held for several months while the National Convention got back into some control and then released.
Naturally he did the same sort of propaganda work for Napoleon and the Empire, only larger---vast yards upon yards of canvas. Later when the Revolution and Empire folded, he turned to painting kindly portraits of the nouvelle bourgeoisie. A man for all seasons.
There are Lev Davidovich Bronstein and Andre Malraux, not exactly heads of state, but up on top and they were both great writers.
CG