How was the disagreement over Missouri's statehood an example of sectionalism?

The disagreement over Missouri's statehood exemplified sectionalism as it highlighted the deepening divide between the North and South over the issue of slavery. When Missouri applied for statehood in 1819, the proposal to allow slavery sparked intense debate, reflecting the North's desire to limit the expansion of slavery and the South's commitment to maintaining and expanding it. The Missouri Compromise of 1820, which allowed Missouri to enter as a slave state while Maine entered as a free state, underscored the growing tensions and the need to balance power between free and slave states, revealing the sectional interests that threatened national unity.