Isaac Gewirtz, in Mark Twain A Skeptic's Progress, writes of Twain's view of the French Revolution:

Reflections on his visit to New Orleans (“Enchantments and Enchanters”) [Chapter 46 of Life on the Mississippi] naturally draw his attention to France.  Reactionaries in America, as well as in Britain and Europe, had long attempted to taint the achievements of the French Revolution and Napoleon, the world-conquering general who was its creature, with the bloodshed and suffering that they caused. But Twain believes that the excesses of the Revolution and of Napoleon were redeemed by “two compensating benefactions.” The Revolution “broke the back of the ancient régime and of the Church and made a nation of slaves a nation of freemen; and Bonaparte instituted the setting of merit above birth, and also so completely stripped the divinity from royalty” that Europe’s monarchs, who had been regarded as “gods,” would henceforth be regarded as mere men, “and can never be gods again [. . .] and [are now] answerable for their acts like common clay”. Twain had originally written: “it broke the chains of the ancien regime of the Church, & made of a nation of abject slaves a nation of freemen.” The manuscript was emended in the published text, with Twain forsaking the slavery metaphor of “broke the chains” for the more violent “broke the back.” But the manuscript was also softened in the published text by the removal of the adjective “abject.”

Twain casually dismisses as “temporary harms” the excesses of the Revolution and of Bonaparte, proclaiming the world to be a much better place for their “permanent services to liberty, humanity, and progress.”