History: American Civil War (1861-1865)

Antislavery forces in the North identified the "Slave Power" as a direct threat to republican values. They argued that rich slave owners were using political power to take control of the Presidency, Congress and the Supreme Court, thus threatening the rights of the citizens of the North.
Free soil
"Free soil" was a Northern demand that the new lands opening up in the west be available to independent yeoman farmers and not be bought out by rich slave owners who would buy up the best land and work it with slaves, forcing the white farmers onto marginal lands. This was the basis of the Free Soil Party of 1848, and a main theme of the Republican Party.