In 1854 , the Kansas – Nebraska Act , which opened the new territories to slavery , was passed . Southern Whigs generally supported the Act while Northern Whigs remained strongly opposed . Most remaining Northern Whigs , like Lincoln , joined the new Republican Party and strongly attacked the Act , appealing to widespread Northern outrage over the repeal of the Missouri Compromise . Other Whigs joined the Know Nothing Party , attracted by its nativist crusades against so-called " corrupt " Irish and German immigrants . In the South , the Whig Party vanished — but as Thomas Alexander has shown , Whiggism as a modernizing policy orientation persisted for decades . Historians estimate that in the South in 1856 former Whig Fillmore retained 86 percent of the 1852 Whig voters when he ran as the American Party candidate . He won only 13 % of the Northern vote , though that was just enough to tip Pennsylvania out of the Republican column . The future in the North , most observers thought at the time , was Republican . Scant prospects for the shrunken old party seemed extant and after 1856 virtually no Whig organization remained at the regional level . Twenty-six states sent 150 delegates to the last national convention in September 1856 . The convention met for only two days and on the second day ( and only ballot ) quickly nominated Fillmore for President , who had already been nominated for President by the Know Nothing Party . Andrew Jackson Donelson was nominated for Vice President . Some Whigs and others adopted the mantle of the Opposition Party for several years and enjoyed some individual electoral successes
national convention
1856 Whig National Convention
Whig Party (United States)