A new book documents that before the Civil War, “Southern politicians and pro-slavery ambitions shaped the foreign policy of the United States in order to protect slavery at home and advance its interests abroad.” The book is “This Vast Southern Empire: Slaveholders at the Helm of American Foreign Policy” by Matthew Karp, Assistant Professor of History at Princeton University.
According to the book’s review in the Wall Street Journal, in this era, “Cuba was a particular obsession for pro-slavery policy makers. The island’s wealth was fabulous—in the 1850s, it produced fully a quarter of the world’s sugar—and slavery was firmly established there. American diplomats tried for years to purchase the island outright and forestall any attempt at emancipation by Cuba’s Spanish rulers. ‘We regard an attempt . . . to blast with the plague of emancipation that garden of the West, as a crime against civilization,’ wrote the Charleston Mercury, a frequent mouthpiece for pro-slavery opinion.”
Indeed, says Karp, few southern leaders “believed that the United States could digest a meal so unpalatable as a free black Cuba.”
 Harvard Univ. Press, This Vast Southern Empire: Slaveholders at the Helm of American Foreign Policy (Sept. 2016); Bordewich, Dixie’s Foreign Policy, W.S.J. (Dec. 12, 2016).