The '''Supremacy Clause''' of the [[Constitution of the United States]] ([[Article Six of the United States Constitution#Supremacy|Article VI, Clause 2]]) establishes that the Constitution, [[Law of the United States|federal laws]] made pursuant to it, and [[Treaty|treaties]] made under its authority, constitute the "supreme Law of the Land", and thus take priority over any conflicting [[State law (United States)|state laws]].<ref name=A6C2NCC>{{Cite web| title=The Supremacy Clause| last1=Nelson| first1=Caleb| last2=Roosevelt| first2=Kermit| url=https://constitutioncenter.org/interactive-constitution/article/article-vi| publisher=National Constitution Center| location=Philadelphia, Pennsylvania| access-date=October 10, 2019}}</ref> It provides that [[State court (United States)|state courts]] are bound by, and [[State constitution (United States)|state constitutions]] subordinate to, the supreme law.<ref>{{cite book| last=Burnham| first=William| title=Introduction to the Law and Legal System of the United States| edition=4th| date=2006| publisher=Thomson West| location=St. Paul, Minnesota| page=41}}</ref> However, federal statutes and treaties must be within the parameters of the Constitution;<ref>{{Cite web|title=Interpretation: The Supremacy Clause {{!}} The National Constitution Center|url=https://constitutioncenter.org/interactive-constitution/interpretation/article-vi/clauses/31|access-date=2021-12-29|website=constitutioncenter.org|quote=Under the Supremacy Clause, the “supreme Law of the Land” also includes federal statutes enacted by Congress. Within the limits of the powers that Congress gets from other parts of the Constitution, Congress can establish rules of decision that American courts are bound to apply, even if state law purports to supply contrary rules. Congress also has at least some authority to put certain topics wholly off limits to state law, or otherwise to restrict what state law can validly say about those topics. As long as the directives that Congress enacts are indeed authorized by the Constitution, they take priority over both the ordinary laws and the constitution of each individual state.}}</ref> that is, they must be pursuant to the federal government's [[enumerated powers]], and not violate other constitutional limits on federal power, such as the [[United States Bill of Rights|Bill of Rights]]—of particular interest is the [[Tenth Amendment to the United States Constitution]], which states that the federal government has only those powers that are delegated to it by the Constitution.<ref>{{Cite web|title=Suspect Spheres, Not Enumerated Powers: A Guide for Leaving the Lamppost|url=https://michiganlawreview.org/journal/suspect-spheres-not-enumerated-powers/|date=2024-02-24|website=Michigan Law Review|language=en-US}}</ref> It is the responsibility of the [[United States Supreme Court]] in that case to exercise the power of [[Judicial review in the United States|judicial review]]: the ability to invalidate a [[statute]] for violating a provision of the [[Constitution of the United States|Constitution]].

As a constitutional provision announcingidentifying the supremacy of federal law, the Supremacy Clause assumes the underlying priority of federal authority, albeit only when that authority is expressed in the Constitution itself;<ref>{{cite book|title=Fundamentals of American law|year=1998|chapter=Preemption Controversies|chapter-url=https://books.google.com/books?id=Si0lupMPrEoC&q=federal+preemption&pg=PA31 | first1=Alan B. | last1=Morrison | page=31 | isbn=978-0-19-876405-2 | publisher=Oxford University Press US}}</ref> no matter what the [[Federal government of the United States|federal]] or [[State governments of the United States|state governments]] might wish to do, they must stay within the boundaries of the Constitution.<ref>{{Cite web|date=2012-04-13|title=The Priority of the Constitution over Federal Statutes - Mike Rappaport|url=https://lawliberty.org/the-priority-of-the-constitution-over-federal-statutes/|access-date=2022-01-11|website=Law & Liberty|language=en-US|quote=During the ratification, various Federalists urged that "in pursuance" of the Constitution meant not just conformity with bicameralism and presentment, but otherwise consistent with the entire Constitution. Only such latter statutes were entitled to be treated as supreme over contrary state law. See, for example, Jensen, ed, 2 Documentary History of the Ratification at 517 (cited in note 59) (James Wilson commenting that “in pursuance” meant that a law was otherwise constitutional). Earlier, Wilson had claimed that Congress could not pass any laws restricting the press because such laws would not be in “pursuance” of the Constitution. Id at 455. See also Jonathan Elliot, ed, 4 The Debates in the Several State Conventions on the Adoption of the Federal Constitution 188 (2d ed 1836) (Governor Johnston of North Carolina commenting that every law consistent with the Constitution is “made in Pursuance” of it; those laws inconsistent are not made in Pursuance of it); id at 182 (William Davie commenting to the same effect); id at 28, 178–79 (James Iredell commenting to the same effect); Federalist 33 (Hamilton), in The Federalist 203, 207 (Wesleyan 1961) (Jacob E. Cooke, ed) (claiming that laws that are not pursuant to the Constitution, but instead invade state power, are acts of usurpation).}}</ref> Consequently, the Supremacy Clause is considered a cornerstone of the [[Federalism in the United States|United States' federal political structure]].<ref>{{cite book |first=W. Cleon |last= Skousen |title=The Making of America – The Substance and Meaning of the Constitution |url=https://archive.org/details/makingofamericas00skou |url-access=registration |publisher=National Center for Constitutional Studies |location=Washington D.C. |year=1985 |page=[https://archive.org/details/makingofamericas00skou/page/657 657]|isbn= 9780934364669 }}</ref><ref>{{Cite book|title=The Supremacy Clause: A Reference Guide to the United States Constitution|last=Drahozal|first=Christopher R.|date=2004|publisher=Greenwood Publishing Group|isbn=9780313314476|page=xiv|url=https://books.google.com/books?id=bAhi1GbCldsC&q=The+Supremacy+Clause:+A+Reference+Guide+to+the+United+States+Constitution}}</ref>