The Conscience Whigs was a New England-based faction of the Whig party known for their moral opposition to slavery. They also opposed the Mexican war and the annexation of Texas, fearing that the resulting extension of slavery would harm the republic.
The group split from the Whig party when the slave-owning General Zachary Taylor was nominated for President in 1848. That same year, the Conscience Whigs helped create the Free Soil Party, which nominated Conscience Whig leader Charles Francis Adams for president. The Free Soil Party, however, soon failed, and many Conscience Whigs returned to the Whig party. There, many of their leaders helped lay the foundation for what would be the Republican Party in 1854.