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.Ratified in 1791 along with the rest of the Bill of Rights, the tenth amendment states in general terms certain limits to the powers of the federal government. Disagreement over the exact interpretation of the tenth amendment began fairly quickly. When Hamilton proposed a national bank along the lines of the Bank of England, President Washington was concerned about the constitutionality and asked the two leaders of his cabinet, Secretary of the Treasury Alexander Hamilton and Secretary of State Thomas Jefferson, to advise him. In Jefferson's opinion, there were many specific defects to the bank but the point of lasting interest concerns the unconstitutionality (in Jefferson's opinion) due to the tenth amendment:
I consider the foundation of the Constitution as laid on this ground: That " all powers not delegated to the United States, by the Constitution, nor prohibited by it to the States, are reserved to the States or to the people." [XIIth amendment.] To take a single step beyond the boundaries thus specially drawn around the powers of Congress, is to take possession of a boundless field of power, no longer susceptible of any definition.Jefferson referred to the 12th amendment because he was writing before final ratification, at which time two amendments were not ratified and the original 12th became the 10th. Hamilton was equally certain that the bank was permitted:Now it appears to the Secretary of the Treasury, that this general principle is inherent in the very definition of Government and essential to every step of the progress to be made by that of the United States, namely--that every power vested in a Government is in its nature sovereign, and includes by force of the term, a right to employ all the means requisite, and fairly applicable to the attainment of the ends of such power; and which are not precluded by restrictions and exceptions specified in the constitution, or not immoral, or not contrary to the essential ends of political society.The Supreme Court used the tenth amendment to strike down many acts of Congress that tried to implement progressive reforms on a national level. The disagreement reached crisis proportions during the Franklin D. Roosevelt's first term, when the Supreme Court struck down as unconstitutional many of the important features of the New Deal. FDR was prepared to pack the court with new and pliable justices, but public opinion persuaded him to abandon the attempt. It became unnecessary when the court reversed course and gave approval in Roosevelt's second term in cases similar to ones they had struck down earlier.
See Table of Amendments.