Leading Up to the Civil War By caboose31 Aug 8, 1846 Wilmot Priviso May 12, 1848 Treaty of Guadalupe-Hidalgo May 12, 1850 Comprimise of 1850 May 12, 1854 Kansas-Nebraska Act May 24, 1856 Pattawotamie Massacre May 12, 1858 Lincoln-Douglas Election May 12, 1859 Harpers Ferry May 12, 1860 Lincoln Elected President May 12, 1860 South Carolina secedes from Union