Explain what Americans meant when they referred to the Slave Power and trace the fear of Slave Power from Mexican War through the 1860 presidential election. To what extent was this fear justified?

Slave Power was a conspiracy in the eyes of the North. Beginning with the Gag Rule that tabeled all talk of abolition in Congress and continuing with the Supreme Court rule in the case of Dred Scott vs. Sanford that stated that the Missouri Compromise was unconsitutional, the Northern states basically believed that the South wished to have all states be slave states so that they could have all of the power in the House. The Mexican War affected this belief in that President Polk declined to give out full information regarding the war to cause the war to be declared with less delay. Also, Polk had threatened war with Great Britain to receive control of Northern areas; instead of getting all the land that was in dispute, Polk settled. That was fine until he waged a war to get the Southerners more land; why fight for the South but not the North?