WHEN KARL MARX MADE THE CASE FOR CAPITALISM THE COMMUNIST MANIFESTO AUTHOR BELIEVED FREE LABOR WAS SUPERIOR TO SLAVERY.

• Author: Root, Damon

IN NOVEMBER 1864, Karl Marx wrote a letter congratulating President Abraham Lincoln on his reelection to the White House. "From the commencement of the titanic American strife the workingmen of England felt instinctively that the star-spangled banner carried the destiny of their class," Marx declared. He was therefore thrilled by the news that Lincoln would continue "to lead his country through the matchless struggle for the rescue of an enchained race and the reconstruction of a social world."

That reconstructed social world did not just involve a Union victory in the Civil War. What Marx had in mind was the triumph of the North's free labor system and the accompanying spread of Northern capitalism throughout the would-be Confederate States of America.

If the idea of Marx welcoming the spread of capitalism comes as a surprise, that's because you don't know Marx. The free market economist Joseph Schumpeter famously likened capitalism to a "gale of creative destruction." But Marx actually said something similar in The Communist Manifesto, co-written with Friedrich Engels in 1848.

In barely a century, they wrote, capitalism "has created more massive and more colossal productive forces than have all preceding generations together." It has "rescued a considerable part of the population from the idiocy of rural life" and "wherever it has got the upper hand, has put an end to all feudal, patriarchal" arrangements. "All fixed, fast-frozen relations, with their train of ancient and venerable prejudices and opinions are swept away," and "all new-formed ones become antiquated before they can ossify. All that is solid melts into air."

According to Marx, history unfolded in a grand series of stages, each defined by its dominant mode of economic production and each specifically arising to replace the one that preceded it. "In broad outlines," he wrote in the preface to A Contribution to the Critique of Political Economy, "ancient, feudal, and modern bourgeois modes of production can be designated as progressive epochs in the economic formation of society." Capitalism, in other words, was a historically necessary step in human progress.

The great revolutionary forces unleashed by capitalism, Marx thought, would in turn form and shape a self-aware proletariat class that would ultimately lead humanity into a glorious communist future. But that would happen only after capitalism had worked its magic. "No social order ever perishes," Marx maintained, "before...