The Tenth Amendment is the Constitution’s clearest endorsement of federalism: “The powers not delegated to the United States by the Constitution, nor prohibited by it to the States, are reserved to the States respectively, or to the People.”
The Tenth Amendment underscores the principle that the national government is one of limited, enumerated powers, and does not have the authority to exceed those powers. The Constitution makes clear that the states and the people are the ultimate residuary of all powers not specifically delegated to the federal government.
In the early days of the country, most Americans remembered the tyrannical government of Great Britain and consistently protected the sovereignty of the states. Beginning with President Franklin D. Roosevelt’s “New Deal” programs, many people became dependent on federal dollars. The Great Depression led many people to look to the federal government to play a bigger role in order to stave off extremely hard times. In doing so, Americans inadvertently deserted the Tenth Amendment’s principles limiting the role of the federal government.
Under the purview of the Commerce Clause, the Necessary and Proper Clause, and the Taxing and Spending Clause of the Constitution, the federal government now oversees many of the functions previously regulated by the states, including commerce, manufacturing, transportation, national resource management, education, and healthcare. While these controls initially began out of the need for jobs and a social safety net, the federal government maintained and increased control over these functions by attaching mandates to the appropriations states rely upon to implement the federal regulations.
The Institute for Policy Innovation on the purpose and importance of the 10th Amendment:
It’s the last of the first 10 amendments to the U.S. Constitution, known as the Bill of Rights, proposed by Congress in 1789 and ratified by the legislatures of the several states. The Tenth Amendment affirms the Union is a nation of states. The states cede some of their inherent authority over specific issues (e.g., defense and interstate commerce) to the federal government. All of the rights and responsibilities not specifically delegated to the federal government are reserved to the states or to the people, not the other way around. The Tenth Amendment reinforces, and in fact helps define, the Founding Fathers’ plan for a nation with a diversity of power centers, unlike the basically unitary, top-down monarchies of 18th century Europe.