Surprisingly, Kaldellis identifies Jean-Jacques Rousseau as the Western theorist closest to the Byzantine tradition, citing passages from The Social Contract that do sound somewhat Byzantine.

Rousseau defines a republic as “any state ruled by laws, whatever may be the form of administration.” He assigns sovereignty to the people and makes government their minister. And he stresses the importance of moral consensus and sees a need for a civil religion.

When he writes that the most important laws are not those written down but those “in the hearts of the citizens,” Kaldellis says, Rousseau “reveals himself a classical rather than a modern thinker.”

This is a rather superficial reading of Rousseau. Byzantium was an actual, historical reality—a particular people with a particular past, religion, and legal, political, and cultural tradition—whereas Rousseau’s republic is yet another modern Western theoretical ideal, based on a very un-Roman, un-Christian, and un-Byzantine understanding of human nature and history.

In his theoretical republic, all issues of value defining the common good are settled by the “general will,” which is not bound by any religion, tradition, institution, constitution, contract, or even reality.

The people are free to build a new civilization as they please; they just need an enlightened lawgiver to show them how. (Rousseau saw himself in that role and actually offered his assistance in revolutionary lawgiving to Poland and Corsica.)

But what Kaldellis sees in Rousseau—the idea of a people expressing their will in the Byzantine way, asserting their sovereignty over the government extralegally—is why Rousseau still rivals Marx as the chief prophet of progressivism, and why progressive academics can be expected to embrace Kaldellis’s recasting of the Byzantines as secular democrats.