Polygenism rose as the Fugitive Slave Act was debated

Evidence

[The year] 1850 was a pivotal moment for polygenists and the political implications of their theory. The Fugitive Slave Act, widely seen as a barometer of the relative strength of the pro-slavery and abolitionist camps, was being hotly debated in Congress. — Tamara Lanier, From These Roots, 1058

Categorization

• XREF: Shows the political context within which the 1850 photographs of Renty and Delia were produced — sets up the book’s core claim about images as property and evidence.