After eleven of the thirteen original states ratified the Constitution (North Carolina and Rhode Island did not ratify the document until later in 1789 and in 1790, respectively) and the federal government began operating, Congress turned to consider amendments that were intended to address some of the concerns expressed by Antifederalist critics of the Constitution during the ratifying debates. James Madison (1751–1836) introduced in the House of Representatives a series of proposed amendments, including the provision that became the Tenth Amendment. He explained the purpose of this amendment during a June 8, 1789, speech proposing the Bill of Rights: “I find, from looking into the amendments proposed by the state conventions, that several are particularly anxious that it should be declared in the Constitution, that the powers not therein delegated should be reserved to the several states. Perhaps words which may define this more precisely than the whole of the instrument now does, may be considered as superfluous. I admit they may be deemed unnecessary: but there can be no harm in making such a declaration, if gentlemen will allow that the fact is as stated. I am sure I understand it so, and do therefore propose it.”

As originally proposed, what became the Tenth Amendment read: “The powers not delegated by the Constitution, nor prohibited by it to the states, are reserved to the states respectively.” When the House debated this language, several members sought to add the word “expressly,” with the intent of making clear that state governments or the people retained all powers “not expressly delegated by this Constitution.” In an argument that proved persuasive to a majority of the chamber, Madison argued against including “expressly” in the amendment. The final text of the amendment, as it emerged from Congress and was ratified by state legislatures, declares: “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 has been invoked throughout American history by officials, and especially judges, in the course of considering the legitimacy of federal acts (see, for instance, Executive Order 12612, Gregory v. Ashcroft, and Printz v. United States). However, the Supreme Court concluded in its most direct engagement with the Tenth Amendment (U.S. v. Darby, 312 U.S. 100 (1941)) that it is not judicially enforceable. In his opinion for the Court in that case, Justice Harlan Stone wrote: “The amendment states but a truism that all is retained which has not been surrendered. There is nothing in the history of its adoption to suggest that it was more than declaratory of the relationship between the national and state governments as it had been established by the Constitution before the amendment, or that its purpose was other than to allay fears that the new national government might seek to exercise powers not granted, and that the states might not be able to exercise fully their reserved powers.”