Immigrant workers in eastern cities and those who lived in the southern parts of the midwest had little sympathy for abolitionism or blacks, supporting the antiwar stance of the peace democrats, often referred to as .

Copperheads

Explanation:

The term copperhead was used by Republicans in the 1860s for a faction of anti-war democrats. There were two factions developed in the Democratic party those who supported it were called war democrats and those who opposed it were called copperheads. Copperheads were in favor of compromise between the Union and Confederacy. Their power was mainly accumulated in Midwest and they oppose abolitionism because of the threat to lose their jobs to free slaves of the South.

the  wilmot proviso  was designed to eliminate  slavery  within the  landacquired as a result of the mexican war (1846-48). fearing the addition of a pro-slave territory, pennsylvania congressman david  wilmot proposedhis amendment to the bill.