Final answer:
The Fourteenth Amendment and the Civil War Amendments collectively shifted power away from states and toward the federal government, ensuring federal oversight in the protection of citizens' rights.
Step-by-step explanation:
The amendment that represented a shift in power away from states and toward the federal government is the Fourteenth Amendment. Ratified in 1868, this amendment significantly changed the balance of power between the federal government and the states, particularly in its provisions for equal protection and due process guarantees to citizens, which limited state powers and expanded federal oversight.
Furthermore, the Civil War Amendments (Thirteenth, Fourteenth, and Fifteenth) as a whole emphasized federal authority in protecting citizens' rights, thereby reducing states' autonomous powers that could conflict with these rights