American slavery’s nineteenth-century expansion foreshadowed global capitalist development.

Evidence

Du Bois came to believe that the preservation of the capitalist world system, its very expansion in the nineteenth and twentieth centuries, had involved the absorption of new sources of labor power, not by their conversion into wage labor but by coercion. … The expansion of American slavery in the nineteenth century was not an anachronism but a forewarning. But so too, he believed, was its defeat. — Cedric J. Robinson, Black Marxism_ The Making of the Black…, 1129

Categorization

• ADDENDUM: Supports the reader’s causal goal: Du Bois reads antebellum America as a microcosm of the world system — useful background for the tradition’s rise.
• XREF: connects to: American territorial expansion, slavery, and cotton drove the Industrial Revolution symbiotically — Deepa Kumar, Islamophobia and the Politics of…, 199