The Tenth Amendment to the United States Constitution, ratified in 1791 as part of the Bill of Rights, establishes the principle of federalism by clarifying the division of power between the federal government and the states. It states that any powers not delegated to the federal government by the Constitution, nor prohibited to the states, are reserved to the states or the people. This means the federal government only has the powers explicitly granted by the Constitution, and all other powers belong to the states or the people

. The amendment was intended to limit the scope of federal authority and reassure those concerned about a strong central government by affirming that states retain significant powers. It serves as a constitutional foundation for states' rights and has been cited in Supreme Court cases to assess whether the federal government has overstepped its constitutional bounds

. In summary, the Tenth Amendment:

• Reinforces federalism by reserving unspecified powers to states or the people.
• Limits federal government powers to those specifically enumerated in the Constitution.
• Protects states' rights against federal overreach.
• Has played a key role in constitutional debates and court decisions about the balance of power between federal and state governments