How did the Mexican Cession impact politics about slavery?

The Mexican Cession, acquired through the Treaty of Guadalupe Hidalgo in 1848, intensified the national debate over slavery in the United States. The new territories raised contentious questions about whether to permit slavery, leading to proposals like the Wilmot Proviso, which sought to ban slavery in these lands. This conflict contributed to the fracturing of political parties, particularly the rise of the Free Soil Party and the eventual realignment of the Democratic and Whig parties. Ultimately, the tensions over slavery in the Mexican Cession played a significant role in escalating the national crisis that led to the Civil War.