The Tenth Amendment

The Tenth Amendment reserves to the states, or to the people, all powers not delegated to the federal government by the Constitution. It is the textual anchor of American federalism.

The Tenth Amendment reads in full: "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." It states a structural principle that is implicit in the rest of the document. The federal government has enumerated powers. Whatever it has not been granted, it does not have. The amendment was added to reassure those who feared the new national government would absorb the prerogatives of the states. For most of the nineteenth century, the Tenth Amendment was treated as a meaningful limit on federal authority. The Supreme Court struck down a number of federal laws as encroaching on state powers. That changed during the New Deal, when the Court began upholding broad federal regulation of the economy under the Commerce Clause. For roughly half a century after 1937, the Tenth Amendment was treated as a truism rather than a constraint. Beginning in the 1990s, the Court began enforcing the amendment again. In New York v. United States in 1992 and Printz v. United States in 1997, the Court held that the federal government cannot "commandeer" state legislatures or state officers to carry out federal programs. NFIB v. Sebelius in 2012 used a similar principle to hold that Congress could not force states to expand Medicaid under the Affordable Care Act. The Tenth Amendment does not say what the federal government may do. It says, in essence, that whatever the federal government does, it must find authority for it somewhere in the Constitution.