The Mexican-American War nationalized the slavery debate beyond abolitionist circles

Evidence

In the summer of 1847, Garrison wrote in The Liberator that the “slave power” had declined in the past ten years, leading to a “gradual abatement of the prejudice which we have been deploring.” These remarks came in the middle of the Mexican-American War, a battle that began after the United States annexed Texas, and perhaps reflected his anxiety about slavery’s western expansion more than his belief in its imminent demise. The war with Mexico helped nationalize the slavery debate, since many white Northerners who might not have personally supported abolition nevertheless worried that the new territories would be controlled by the enslavers’ interests, shutting out free white labor and increasing the political power of the Southern slaveholding states over the Northern states. Congressional representatives from the North and the South had been in a contentious battle since 1846 over the Wilmot Proviso, which proposed a ban on slavery in any territories acquired during the war. — Nikole Hannah-Jones et al., The 1619 Project, 1263

Categorization

• XREF: The Wilmot Proviso dispute is a structural sister to the Revolutionary-War-cause dispute the reader wants to track — territory acquisition as the mechanism that nationalizes a sectional conflict.