Before the 1860 election, the strength of the republican party was found almost exclusively in the part of the country.

"Following on the heels of the Dred Scott decision of 1857, in which the U.S. Supreme Court voided the Missouri Compromise (1820), thus making slavery legal in all U.S. territories, the election of 1860 was sure to further expose sectional differences between those, especially (but not solely) in the North, who wanted to abolish slavery and those who sought to protect the institution. The Democratic Party held its convention in April–May 1860 in Charleston, S.C., where a disagreement over the official party policy on slavery prompted dozens of delegates from Southern states to withdraw. Unable to nominate a candidate (Sen. Stephen A. Douglas received a majority of the delegates’ support but could not amass the required two-thirds majority needed for nomination), Democrats held a second convention in Baltimore, Md., on June 18–23, though many of the Southern delegates failed to attend. At Baltimore the Democrats nominated Douglas, who easily defeated Kentuckian John C. Breckinridge, the sitting vice president of the United States. Trying to unite Northern and Southern Democrats, the convention then turned for vice president first to Sen. Benjamin Fitzpatrick of Alabama, who declined nomination, and eventually to Herschel V. Johnson, a former U.S. senator and former governor of Georgia, who was chosen as Douglas’s running mate. Disaffected Democrats, largely Southerners, then nominated Breckinridge, with Sen. Joseph Lane of Oregon as his running mate. Both Douglas and Breckinridge claimed to be the official Democratic candidates."