The supremacy clause of Article VI, clause 2, declares: "This Constitution and the Laws of the United States which shall be made in Pursuance thereof; and all Treaties made, or which shall be made, under the authority of the United States, shall be the supreme law of the Land." This principle of national supremacy was a radical departure from the constitutional order that prevailed under the articles of confederation. Whereas the Articles created a short-lived confederation of states—according to its terms a mere "league of friendship" founded on the good faith of sovereign states—the Constitution established a federal union designed to last in perpetuity. The distinguishing feature of the "more perfect union" created by the Constitution was a strong national government capable of dealing with the problems and complexities of a growing nation and strong state governments acting within their sphere of authority. The Constitution does not establish the supremacy of the national government in all things. National supremacy is limited to laws made Pursuant to the Constitution. What is not granted to the national government under its enumerated powers is, as a general rule, reserved to the people or to the states under the tenth amendment.
The supremacy clause may truly be regarded as the linchpin of American federalism. It holds the republic together by providing a principle for the resolution of conflicts between the states and the nation. Valid national law is clearly paramount in the face of conflicting state law. But whether a state law conflicts with federal law or a federal constitutional provision is not always clear. When doubts exist over the compatibility of federal and state law, and a real controversy arises from these doubts, the judiciary is usually called upon to work out the implications of the supremacy clause through interpretation. The outcome of such cases often depends on inferences drawn by the courts from the structure of the federal system and the values it represents.
The problems of interpretation generated by the supremacy clause have taken two forms epitomized by the celebrated cases of mcculloch v. maryland (1819) and gibbons v. ogden (1824). In the first Maryland taxed a national bank doing business within its borders; in the secondNew York granted a monopoly over steamboat navigation on its internal waterways. The supremacy clause operated to invalidate both measures. McCulloch stands for the principle that even a power reserved to the states—here the ordinary and indispensable power of taxation—may not be exercised in such a way as to impede or unduly burden a federal agency or activity; Gibbons stands for the principle that the state's regulation of a subject matter within its territory, and normally under its control, must give way before a conflicting, and valid, federal statute. "It is of the very essence of [national] supremacy," wrote Chief Justice john marshall, "to remove all obstacles to its action within its own sphere, and to so modify every power vested in subordinate governments as to exempt its own operation from … their influence." In both cases, Marshall underscored the plenary nature of the enumerated powers of Congress; they admit of no limitations save those prescribed in the Constitution. When combined with McCulloch 's doctrine of implied powers, fortified by the necessary and proper clause, the reach of federal power cuts a potentially deep furrow into the field of state sovereignty.
This expansive view of federal power was for almost a century strongly contested by the doctrine of dual federalism. It held that nation and states were essentially equal in their respective spheres of influence. The doctrine did not hold that the states could decide for themselves the extent of their sovereign powers. Once again this was a judicial task, for dual federalism was an axiom of constitutional interpretation. Beginning roughly in 1835, shortly after roger b. taney replaced Marshall as Chief Justice, the Supreme Court deployed and developed the concept of state police power—broadly characterized as the power of a state to provide for the general welfare of its people—to limit the reach of national law. This movement attained its apogee in the first third of the twentieth century when the Supreme Court used the Tenth Amendment to invalidate numerous federal laws, all of them regulating various aspects of the economy. Most of these decisions supported the ideology of individualism and capitalism. The national statutes struck down by the Court were deemed to interfere with state police power yet arguably enacted pursuant to the delegated powers of Congress and clearly not expressly forbidden by the Constitution.
The year 1937 marks the collapse of the doctrine that state sovereignty constitutes a limitation on the exercise of power delegated by the Constitution to Congress. Since then the Supreme Court has returned and held steadfastly to the spirit of McCulloch and Gibbons. Even activities sponsored or operated by the state are subject to federal regulation when imposed pursuant to a delegated power. national league of cities v. usery (1976) is the only exception to this principle: in striking down a federal wage and hour provision as applied to state and local public employees, a closely divided Supreme Court ruled that such power—in this instance the federal commerce power—may not be exercised to interfere with "functions essential to the separate and independent existence" of the "states as states." The ghost of dual federalism lurks in Usery. In 1985, however, a closely divided Court overruled Usery in garcia v. san antonio metropolitan transit authority.
In interpreting the supremacy clause today, the Supreme Court has given up the search for bright lines separating federal and state authority. The two levels of government are no longer perceived as antagonistic rivals, whatever the tensions between them. The supremacy clause once operated to immunize persons closely related to the federal government from most forms of state taxation. The pre-1937 doctrine of federal tax immunity, based on the generalized notion of federal supremacy rooted in McCulloch, was construed to invalidate such levies as state or local taxes on the income of federal employees, on interest income from federal bonds, on income derived from property leased by the federal government, and on sales to the United States. Since 1937, however, the Supreme Court with the help of Congress has wiped out most of this reciprocal tax immunity. The prevailing doctrine today, particularly after United States v. New Mexico (1982), is that a nondiscriminatory state tax even upon private contractors with close and intricate relationships with the federal government will not violate the supremacy clause unless the tax is imposed directly upon the United States.
In the field of regulation, too, sharp lines between federal and state authority are often difficult to find. Modern government is complex, involving the entanglement of federal and state policy in fields once regarded as exclusively state concerns. Education, conservation, aid to the poor and the handicapped, and environmental protection are prominent examples of such fields. The relationship between levels of government in all these areas today is one of cooperation and reciprocity. By means of federal grants-in-aid and other funding programs the national government, pursuant to its power of taxing and spending for the general welfare, has actually encouraged the states to pass laws and adopt policies in response to local needs. This new context of cooperative federalism does not mean, however, that the supremacy clause has lost its bite. Indeed, it has operated to establish the primacy of the national government even in some of the aforementioned fields. An example is Blum v. Bacon (1982), where the Supreme Court invalidated a New York law excluding recipients of a federal program aiding poor families with dependent children from receiving aid under the state's federally funded emergency welfare program. (Blum involved a state statutory policy that conflicted with a federal administrative regulation.)
As the preceding suggests, contemporary supremacy clause analysis is largely a matter of statutory interpretation. The supremacy clause has not been interpreted to prevent federal and state governments from regulating the same subject, partly out of the judiciary's recognition of the reality of cooperative federalism. The nature of some subjects (e.g., immigration and naturalization, bankruptcy, patents, and some articles of commerce) may require national uniform legislation. But most problems of American national life are valid topics of both national and state legislation (e.g., air and water pollution, motor carrier transportation, labor relations, consumer protection, and civil rights). States and nation may legislate on these topics for similar or different reasons. The key to the validity of such concurrent or parallel legislation is whether both federal and state regulations can be enforced without impairing federal superintendence of the field. Even apparently conflicting state legislation may survive supremacy clause analysis if the state law deals with a field traditionally occupied by the state and the state's interest is substantial enough to offset any presumption that Congress may have intended to occupy the field all by itself. A principle of comity has thus replaced the earlier antagonism between nation and states characteristic of dual federalism. Today, as a general rule, unless Congress statutorily declares its intent to occupy a field, federal regulation preempts state law only where the latter seriously impedes the former.
Jones v. Roth Packing Company (1977) is a leading example of a case in which federal policy displaced state law notwithstanding the absence of explicit preemptive language in the congressional statute. Here the federal Fair Packaging and Labeling Act, enacted under the commerce clause, was construed to conflict with a state consumer protection law dealing with the weight of certain goods packaged for sale. The Supreme Court read into the federal statute a congressional intent to supersede state law. Supersession was inferred from the supremacy clause because the enforcement of the state law was an obstacle to the full accomplishment and execution of the congressional purpose. In other cases federal preemption has been inferred because "[t]he scheme of federal regulation may be so pervasive as to make reasonable the inference that Congress left no room for the states to supplement it" or because "the Act of Congress may touch a field in which the federal interest is so dominant that the federal system will be assumed to preclude enforcement of state laws on the same subject." The supremacy clause thus remains a vital operative principle of American constitutional law even though the Supreme Court tends to presume the validity of concurrent state legislation, barring proof of its interference with federal policy.
Donald P. Kommers
Corwin, Edwin S. 1913 National Supremacy: Treaty Power versus State Power. New York: Holt.
Schmidhauser, John R. 1958 The Supreme Court as Final Arbiter of Federal-State Relations. Chapel Hill: University of North Carolina Press.