The Tenth Amendment to the United States Constitution grants the states the powers not granted to the Federal Government. It was drafted in 1787 and ratified in 1791 with the rest of the Bill of Rights. This amendment limits the Federal Government to the powers expressly mentioned in the document previously, and gives the states the freedom and power to govern all other matters. It combines with the Ninth Amendment to allay ambiguities in the rest of the Constitution.

Drawing on previous provisions of the Articles of Confederation, the Tenth Amendment has often served as a tool for the states against the Federal Government. States have charged the government with interference in environmental and labor regulations, which the states say the tenth amendment protects them from. These powers are not specifically given to the United States Federal Government by any amendments, and so should belong to the states, many argue.

The Tenth Amendment does not, however, strip from the government implied powers, which are granted under the necessary and proper clause of Article 1 of the Constitution. The Federal Government has often used the Supreme Court and their construction and interpretation of this clause to guarantee them certain rights not mentioned. These rights, claim supporters of the federal government, ought to be held by the national government because they are implied in their power, such as the administration of the military and the handling of foreign affairs and wars.

The Federal Government, though, does yield many powers to the states under the Tenth Amendment. Among these powers are concurrent powers, held by both levels of government, but implemented by states at a more focused level. In some of these cases, however, the Federal Government may intervene or overrule state powers, leading to further state protests of Tenth Amendment infringement.

The states have used the Tenth Amendment in certain cases to repeal a law or decision handed down to them by Federal authorities. Forced participation in a law has been challenged and reversed due to Supreme Court decisions concerning the Tenth Amendment, though it is one of the rarest Constitutional laws brought up in the Supreme Court. The Tenth Amendment has also been used, more frequently, in dealing with matters of commerce and federal funding. The Federal Government has used this amendment often to ensure economic regulations, where conversely the states have done the same to effect uses of state and federal funding.