How did the Polk administration anger the north?

The Polk administration angered the North primarily through its aggressive pursuit of the Mexican-American War, which many Northerners viewed as an attempt to expand slave territory. The war intensified the debate over slavery's expansion into new territories, leading to increased sectional tensions. Additionally, the administration's support for the annexation of Texas, a slave state, further alienated Northern politicians and abolitionists who opposed the spread of slavery. This growing discord contributed to the fracturing of national political unity during the 1840s.