Final answer:
The Civil War resulted in a shift of power towards the central government, as evidenced by the end of states' right to secede and the ratification of the Fourteenth and Fifteenth Amendments.
Step-by-step explanation:
The Civil War between the North and the South had a significant impact on the relationship between state governments and the central government in the United States. The defeat of the South resulted in a shift of power towards the central government. This was evidenced by the end of the right of states to secede and challenge national laws, as well as the imposing of conditions on former Confederate states for re-entry into the Union. These conditions included the ratification of the Fourteenth and Fifteenth Amendments, which further strengthened the power of the central government.