Which amendment affirms that powers not delegated to the national government are reserved to the states?

The Tenth Amendment to the United States Constitution plays a crucial role in the federal structure of the government, establishing the principle of federalism. It explicitly states that powers not granted to the national government, nor prohibited to the states, are reserved for the states or the people. This means that unless the Constitution explicitly gives a power to the federal government, that power remains with the states.

This amendment helps to define the limits of federal authority and ensures that states retain certain powers and rights, thus promoting a balance between state and federal governance. Understanding this principle is vital, as it underscores the importance of state sovereignty and the constitutional protections against an overreaching federal government.

In contrast, the other amendments listed do not address the distribution of powers between the national and state governments. The First Amendment covers freedoms concerning religion, expression, assembly, and the right to petition, the Fifth Amendment focuses on legal protections including due process and self-incrimination, and the Second Amendment addresses the right to bear arms. Each of these serves different purposes and does not relate to the reservation of powers to the states.