On the eve of the American Revolution, slavery was recognized and accepted throughout the New World. All of the major European powers at one time or another entered the Atlantic slave trade, just as most of them possessed slave colonies. Yet it was the British who came to dominate the Atlantic slave system. British Empire ships carried more African captives than any nation (an estimated three million); Britain's colonies in the Caribbean and mainland North America produced vast quantities of tropical goods (sugar, tobacco, rice, indigo) for the home market; and the country as a whole grew rich on the profits of enslaved African labor.
Within two decades, however, Britain (1807) and the United States (1808) had acted decisively to abandon the transatlantic slave trade. In fact, "abolition" was to emerge as one of the most important reform movements of the eighteenth and nineteenth centuries.
How and why this came about are questions that continue to puzzle historians. By and large, interpretations of abolition tend to fall into two camps. The first, popularized during the nineteenth century, tends to explain abolition in terms of a moral or humanitarian movement.
The second, which can be traced back to the publication of Eric Williams's book Capitalism and Slavery, in 1944, places much greater emphasis on economic factors. Controversially, Williams argued that abolition coincided with periods of general economic decline in the British Caribbean. Abolition, in other words, was motivated purely by economic self-interest. Williams's "decline thesis" remains a subject of ongoing historical inquiry. But if many of his arguments have been questioned, Williams was surely right in drawing attention to the connection between abolition and capitalism.
This is not to suggest that the spread of abolitionist ideas had to rest on the growth of the factory system and free-labor ideology, but that there was a link of some sort, perhaps a transformation of consciousness, evident in the desire on both sides of the Atlantic to dignify and honor labor, now seems indisputable. Abolition is perhaps best understood as the confluence of a number of different factors, some of them moral, some of them economic, and some of them ideological.