1. Wilmot Proviso- A plan that some northerners wanted to prohibit slavery in all parts of the Mexican Cession.
2. Sectionalism- A devotion to the interests of one region instead of to the country as a whole—over the issue of slavery.
3. Popular sovereignty- would allow voters in a territory to decide whether they wanted to ban or permit slavery. They would make their decision by electing antislavery or pro-slavery representatives to their territorial legislatures. Based on the will of the majority, these legislatures then pass laws to prohibit or promote slavery.
4. Free-Soil Party- This political party formed when the Whigs and democrats refused to address the slavery issue. They endorsed the Wilmot