From Greg Grandin’s fantastic The Empire of Necessity (Holt, 2013)

“Writing in the 1970s, Yale’s Edmund Morgan was one of the first modern historians to fully explore what he called the “central paradox” of this Age of Liberty: it also was the Age of Slavery. Morgan was writing specifically about colonial Virginia, but the paradox can be applied to all of the Americas, North and South, the Atlantic to the Pacific, as the history leading up to and including events on the Tryal reveals. What was true for Richmond was no less so for Buenos Aires and Lima—that what many meant by freedom was the freedom to buy and sell black people as property.

To be sure, Spain had been bringing enslaved Africans to the Americas since the early 1500s, long before subversive republicanism, along with all the qualities that a free man was said to possess—rights, interests, free will, virtue, and personal conscience—began to spread throughout America. But starting around the 1770s, the slave trade underwent a stunning transformation. The Spanish Crown began to liberalize its colonial economy and the floodgates opened. Slavers started importing Africans into the continent any which way they could, working with privateers to unload them along empty beaches and in dark coves, sailing them up rivers to inland plains and foothills, and marching them over land. Merchants were quick to adopt the new language associated with laissez-faire economics to demand the right to import even more slaves. And they didn’t mince words saying what they wanted: they wanted más libertad, más comercio libre de negros—more liberty, more free trade of blacks.

More slaves, including Babo, Mori, and the other Tryal rebels, came into Uruguay and Argentina in 1804 than any year previous. By the time Amasa was cruising the Pacific, a “slavers’ fever,” as one historian has put it, had taken hold throughout the continent. Each region of America has its own history of slavery, with its own rhythms and high points. But taking the Western Hemisphere as a whole, what was happening in South America in the early 1800s was part of a New World explosion of chattel bondage that had started earlier in the Caribbean, and was well under way in Portuguese Brazil. After 1812, it would hit the southern United States with special force, with the movement of cotton and sugar into Louisiana and across the Mississippi, into Texas.

In both the United States and Spanish America, slave labor produced the wealth that made independence possible. But slavery wasn’t just an economic institution. It was a psychic and imaginative one as well. At a time when most men and nearly all women lived in some form of unfreedom, tied to one thing or another, to an indenture, an apprentice contract, land rent, a mill, a work house or prison, a husband or father, saying what freedom was could be difficult. Saying what it wasn’t, though, was easy: “a very Guinea slave.” The ideal of the free man, then, answerable to his own personal conscience, in control of his own inner passions, liberated to pursue his own interests—the rational man who stood at the center of an enlightened world—was honed against its fantasized opposite: a slave, bonded as much to his appetites as he was to his master. In turn, repression of the slave was an often repeated metaphor for the way reason and will must repress desire and impulse if one were to be truly free and be able to claim equal standing within a civilization of similarly free men.

It might seem an abstraction to say that the Age of Liberty was also the Age of Slavery. But consider these figures: of the known 10,148,288 Africans put on slave ships bound for the Americas between 1514 and 1866 (of a total historians estimate to be at least 12,500,000), more than half, 5,131,385, were embarked after July 4, 1776.”

(Empire of Necessity, 6-8)