Sectional Discord and the Decline of Manifest Destiny
In the later 1840s and 1850s, Whig politicians united behind the idea of commercial empire. They pushed for control of international trade rather than territory. Democratic politicians, by contrast, frequently fell back on territorial expansionism to unify a coalition fracturing over the question of slavery.
James K. Polk set a standard for annexing land that future Democratic presidential candidates struggled to emulate. New Hampshire Democrat Franklin Pierce, elected in 1852, made territorial expansion an explicit goal. He directed the American minister to Mexico, James Gadsden, to bully or bribe Mexico into selling the United States enough land for a southern route for a transcontinental railroad. The Gadsden Purchase in December 1853 added an extra 45,535 square miles to the Southwest for 10 million dollars. This brought him singular success among Democratic presidents of the era, all of whom hoped to obtain extra land from Mexico after 1848. Democratic presidents repeatedly attempted to purchase Cuba from Spain, but were thwarted by the exploding sectional conflict. When Democratic Senator John Slidell of Louisiana introduced a bill in January 1859 allocating 30 million dollars toward the acquisition of Cuba, it was shot down by Northern opponents.[2360]That the United States did not forcibly take Cuba from Spain in the 1850s can be attributed to sectional discord. Were it not for the fact that the annexation of Cuba would bring another slave state into the Union, Northerners would have happily taken an “island gem” that many considered crucial to American trade and security. But Manifest Destiny forced Americans to take sides over the future of slavery in the republic. While David Wilmot proposed in 1846 that all lands taken from Mexico remain free from slavery, James K. Polk angrily insisted that slavery was a “domestic” matter which had no place in discussions of his war with Mexico. Privately, however, Polk's cabinet agreed that slavery would likely be allowed in lands taken from Mexico. Divisions between North and South exploded in the contest over the issue, and Northerners were no longer amenable to any territorial acquisition that might strengthen the South. Each attempt by Southerners to gain new slave territory—and each debate over the status of slavery in the existing territories of the United States—exacerbated the division between North and South.[2361]