During his thirty-year term as a Democratic senator from Missouri (1821–51), Thomas Hart Benton was a pivotal proponent of the U. S. expansion beyond its western and southern borders. For Benton and other supporters of what came to be known as “manifest destiny,” the country’s growth was inevitable. Benton promoted annexing new territories, homesteading by European Americans, and other measures—all of which displaced Native Americans from their lands.
While Benton’s career flourished as the country expanded, it later faltered on the issue of slavery. Although Benton enslaved people, he nevertheless supported the Union and objected to introducing slavery to new states and territories. Accordingly, he voted against the Compromise of 1850, a set of five bills that kept slavery in some new parts of the country and forestalled the decision to allow it in others. Outraged by Benton’s vote, the Missouri legislature replaced him with a pro-slavery member of the Whig party.