The historical conflict that initiated debates over slavery and states' rights before the Civil War was the Missouri Compromise. This conflict arose as Missouri sought statehood, prompting disputes about the extension of slavery into new territories. The compromise aimed to maintain a balance between free and slave states but ultimately highlighted the growing sectional tensions. This discord foreshadowed larger confrontations, leading to the Civil War. Issues surrounding slavery and the rights of states versus federal authority became central elements in American political discourse during this period.