Why did Political tensions and debates surrounded territorial expansion of the US leading up to the civil war because?

Political tensions and debates over territorial expansion in the U.S. leading up to the Civil War were primarily driven by the contentious issue of slavery. As new territories were acquired, questions arose about whether they would be admitted as free or slave states, heightening sectional divisions. The Missouri Compromise and the Kansas-Nebraska Act exemplified these conflicts, as they aimed to balance power between slave and free states but ultimately fueled further discord. This struggle over expansion not only intensified regional rivalries but also set the stage for the violent confrontations that characterized the Civil War.