I was writing a memo just now, I wrote an unique and I just stopped and looked at it and realized it was wrong. My whole world had been turned upside down. Then I found this explanation and all is right with the world.
Liberty Party (1840) wanted to abolish slavery; Free Soil Party (1848) wanted to keep slavery from expanding into Western territories; American Party (Know-Nothings in 1854 & 1856) wanted to reduce immigration (nativism); Constitutional Union Party (1860) wanted a compromise between the North & South.
In 1860 the Democrats split over the slavery issue, as the Northern and Southern wings of the party nominated different candidates (Stephen A. Douglas and John C. Breckinridge, respectively); the election that year also included John Bell, the nominee of the Constitutional Union Party.