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Last Updated: 2006

The removal of one or more legislative, executive, and/or administrative powers by a superior government from one or more inferior governments within a nation or a state is termed “preemption.” A constitution or the legislature of a superior government may preempt completely and/or partially powers of one or more inferior governments or stipulate that a power is superseded only if certain conditions exist within an inferior government. The latter type is known as “contingent preemption.”

Section 10 of Article I of the U.S. Constitution contains an absolute, complete preemption provision: “No State shall enter into any treaty, alliance or confederation, grant letters of marque and reprisal; coin money; emit bills of credit; make any thing but gold and silver coin a tender in payment of debts; pass any bill of attainder, ex post facto law, or law impairing the obligation of contracts, or grant any title of nobility.” The section alternatively can be termed a restraint on the exercise of state powers.

The section also contains a preemption provision that may be waived by Congress granting its consent for states to enter into a interstate compact or a compact with a foreign nation, place a duty on tonnage, or have troops or ships of war “unless actually invaded, or in such imminent danger as will not admit of delay.”

Six constitutional amendments—the Thirteenth, Fourteenth, Fifteenth, Nineteenth, Twenty-fourth, and Twenty-sixth—grant Congress power to enforce the guarantees contained in these amendments and supersede state constitutional provisions and subnational laws as needed. Congress has utilized the preemptive power of Section 5 of the Fourteenth Amendment, in particular, to guarantee the civil rights of all citizens.

In contrast, devolution occurs when a superior government devolves upon inferior governments one or more of its powers. Section 2 of Article IX of the New York State Constitution devolves legislative powers upon general purpose local governments, and Congress has enacted statutes devolving legislative powers upon states; an example is the McCarran-Ferguson Act of 1945, which empowers states to regulate the business of insurance. Furthermore, various congressional preemption statutes devolve specific executive powers upon state governors.

The drafting of the proposed U.S. Constitution in 1787 opened a major debate on the question of the powers to be granted to Congress and whether the proposed regulatory powers should be interpreted broadly or narrowly. Opponents, known as Anti-Federalists, argued these powers could be employed to convert the proposed governance system into a unitary one. Three prominent federalistsAlexander Hamilton, John Jay, and James Madison—wrote a series of letters to editors of New York City newspapers, collectively known as The Federalist Papers, explaining the proposed fundamental law and denying that a unitary system would be established in time if the Constitution is ratified.

Controversy continues to this day with respect to the reach of congressional regulatory powers and is reflected in debates on preemption bills on the floor of the two houses of Congress, and in U.S. Supreme Court decisions interpreting the bounds of congressional regulatory powers. The Court on occasion has reversed its earlier decision holding a congressional statute to be ultra vires, as illustrated by the Court’s 1985 decision in Garcia v. San Antonio Metropolitan Transit Commission overturning its 1976 opinion holding that the application of the Fair Labor Standards Amendments of 1974 to subnational governments violated the Tenth Amendment.

The Constitution established the world’s first federal system by delegating to Congress in broad terms several latent enumerated powers, including the ambiguous Necessary and Proper Clause, and reserved all other powers, unless prohibited, to the states and the people. Congress and the states may exercise concurrent powers, and the former may preempt the concurrent regulatory powers of the latter by exercising a delegated or implied power. Although the power to regulate interstate commerce is a prolific source of preemption statutes, Congress may employ other delegated powers—bankruptcy, copyright, foreign and Indian tribes commerce, naturalization, patent, and taxation—to supersede completely or partially state and local government laws. Alexander Hamilton in The Federalist No. 32 explained that the Constitution grants to Congress the power to enact a statute establishing a uniform rule of naturalization, and hence this power is an exclusive one “because if each state had power to prescribe a distinct rule, there could not be a uniform rule.”

The national legislature, by employing a delegated power prospectively at any time, may preempt completely or partially regulatory powers of states and their political subdivisions. The Constitution’s drafters included the Supremacy of the Laws Clause to resolve conflicts between a state constitution or statute and a treaty with a foreign nation or a congressional statute by nullifying the state constitutional provision or statute. The clause does not grant a regulatory power to Congress. Hence, preemption and supremacy of the law are recognized as distinctive constitutional concepts.

The clause, however, is the source of conflict preemption. Invalidation of a state statute by a court, acting on a case-by-case basis, does not deprive states of their powers to regulate in the given field unless the Court declares that Congress has occupied the field of regulation. Future state enactments in the same regulatory field not occupied completely by Congress, of course, are subject to court challenges if they generate new conflicts. Courts, not Congress, determine whether a conflict is of the magnitude triggering activation of the Supremacy of the Laws Clause. Congress on rare occasions enacts a statute overturning a preemption decision of the Court.

Conflict preemption was the basis for the U.S. Supreme Court’s invalidation of state statutes, commencing with Fletcher v. Peck in 1810, whenever there was a direct conflict between a national statute and a state statute. The failure of Congress to enact interstate commerce statutes, the so-called silence of Congress, led the Court in Cooley v. Board of Port Wardens in 1851 to develop the dormant Commerce Clause doctrine, holding that a state statute may offend the unexercised congressional power to regulate interstate commerce if the subject matters of the statute “are in their nature national, or admit of one uniform system.” Congress is free to reverse a preemption decision of a court based upon the doctrine by validating a state law enactment.

The term “field preemption” first was used by the court in 1912 in Southern Railway Company v. Reid when the Court opined, “Congress has taken possession of the field of regulation,” thereby depriving states of authority to enact any regulatory statute in the field of railroad regulation regardless of whether there is a conflict between the national statute and the state statute. This type of preemption also is referred to as “obstacle preemption,” since the court in Hines v. Davidowitz in 1941 invalidated a state statute because it stood as an obstacle to the achievement of the goals of a congressional statute.

The Necessary and Proper Clause is the source of additional powers confided to Congress and employable to supersede the regulatory powers of subnational governments as the clause permits enactment of preemption statutes not based upon a specific enumerated power. In McCulloch v. Maryland (1819), Chief Justice John Marshall of the U.S. Supreme Court wrote, “[L]et the end be legitimate, let it be within the scope of the Constitution, and all means which are appropriate, which are plainly adapted to that end . . . are constitutional.” This decision clarifies Congress may enact a “field preemption” statute completely depriving state legislatures of authority to enact regulatory statutes in a specified field for the first time.

Preemption statutes often have been the product of lobbying by economic interest groups and in more recent years by civil rights and environmental groups. Congress first employed its complete preemption powers by enacting the Copyright Act and the Patent Act in 1790, but exercised its power of supersession slowly with only twenty-nine complete and partial preemption statutes enacted by 1900, including several that were subsequently repealed. These statutes focused primarily on commerce, health, and safety. An alternative to preemption became common in the twentieth century as Congress attached conditions to numerous grant-in-aid programs to encourage subnational governments to adopt national policies. A total of 134 preemption statutes were enacted between 1900 and 1965 when an explosion in the number of such statutes occurred and Congress concluded that many grant programs had not achieved their goals. The number of such statutes totaled 37 between 1965 and 1969, 102 during the 1970’s, 93 during the 1980’s, 79 during the 1990’s, and 18 between 2000 and 2003. Many of the more recent preemption statutes amend earlier ones.

The failure of Congress, for political reasons, to include an explicit preemption clause in numerous regulatory statutes has produced lawsuits placing the burden upon courts to determine whether the national legislature in enacting each such statute intended to preempt all or a part of the concerned regulatory field. The courts have to divine congressional intent. If the U.S. Supreme Court issues an intent opinion upsetting a majority of the members of Congress, a bill will be introduced and enacted reversing the Court’s decision.

Preemption statutes, by removing a significant number of states’ regulatory powers, produced a silent revolution in the U.S. federal governance system altering fundamentally the balance of national-state regulatory powers. Complete preemption statutes make certain regulatory policies harmonious throughout the nation, and minimum preemption ones, while allowing for a degree of state regulatory discretionary authority, have made state policies more harmonious.

There are fourteen types of complete preemption statutes ranging from ones removing all regulatory authority from states to ones allowing states to cooperate with federal departments and agencies in conducting inspections and/or enforcing federal standards. Several transportation statutes enacted since 1978 are complete deregulation ones providing that the federal and subnational governments will not engage in economic regulation (fares and routes). States, however, are permitted to regulate buses and trucks to ensure they are safe to operate on highways and streets.

In addition, there are eleven types of partial preemption statutes, removing specified regulatory powers from a state while leaving undisturbed other state regulatory powers or establishing minimum national regulatory standards, and one contingent preemption statute. The Voting Rights Act of 1965 is a suspensive or contingent national law applicable to a state or local government only if a literacy test was in effect in 1965 and less than 50 percent of the eligible voters cast ballots in the latest presidential election. It is not unusual for Congress to include a savings clause in what otherwise would be a complete preemption statute, thereby exempting one or more state actions from preemption.

Responding to environmental pollution, Congress designed a new type of preemption statute, termed “minimum standards preemption,” redesigning national-state regulatory relationships. The Water Quality Act of 1965, now the Clean Water Act, authorizes the secretary of the interior (now the Environmental Protection Agency [EPA] administrator) to promulgate rules and regulations establishing nationally uniform water quality standards and to delegate regulatory primacy to a state submitting proposed standards meeting or exceeding the national ones and an enforcement plan demonstrating the competence of its enforcement personnel and the adequacy of needed equipment. If the state standards and enforcement plan are approved, the EPA performs a monitoring role and intervenes only if a state is not enforcing the standards. Minimum standards preemption reflects the principle of subsidiary holding a competent government closest to the people should be responsible for a function. A state is free to return regulatory primacy to the national agency at any time, and a small number of states on occasion have done so. This type of preemption statute also may be labeled a contingent one, based upon the gun behind the door theory, in that the failure of a state to submit an approved plan results in the agency enforcing national standards within the state.

A minimum standards preemption statute is designed to establish a national-state partnership with Congress and a federal department or agency establishing uniform minimum standards throughout the nation, and states are permitted to adopt higher regulatory standards to address unique local conditions. National bureaucrats play an important role because a minimum standards preemption statute, in most cases, is a skeleton one outlining general policy goals and granting department and agency heads authority to promulgate more specific implementing rules and regulations detailing the policy. Drafting the rules and regulations typically involves considerable bargaining between federal and state administrators, and lobbying by interest groups.

Congress also has employed minimum standards preemption in attacking air pollution, drinking water, and surface mining problems. The Air Quality Act of 1967, now the Clean Air Act, is unusual in containing a complete preemption provision in addition to minimum standards preemption. The act preempts the regulation of exhaust emissions from 1968 and subsequent model motor vehicles. The complete preemption provision is the product of lobbying by the motor vehicle manufacturers, who were fearful that they might have to build a different engine or exhaust system for vehicles sold in each of the 50 states.

Congress broke new ground when it enacted the 313-page Clean Air Act Amendments of 1990 containing sections designed to solve the acid rain problem by abandoning the former command and control regulatory system and authorizing each electric utility company whose plants release fewer sulfur dioxide emissions than the maximum allowed to sell sulfur dioxide air pollution credits to another utility company needing the credits to avoid a penalty for exceeding the emissions limit. This trading program is a flexible market-based approach allowing a company to tailor compliance plans to the specific needs of each plant by choosing to burn low-sulfur-content coal, install new emission-abatement equipment, or purchase credits.

Each of a number of preemption statutes contains a mandate (or mandates) requiring subnational governments to initiate a specific action, as illustrated by the Civil Rights Act of 1964. Similarly, a preemption statute may contain one or more restraints forbidding these governments to initiate a specified action. The Ocean Dumping Act of 1988, by prohibiting the dumping of sewage sludge in an ocean, effectively required affected municipalities to employ a more costly alternative disposal method such as incineration or transportation of the sludge to a remote landfill in distant states. Republican Party control of Congress, effective in 1995, resulted in a slight decrease in the preemption statute enactment pace. Furthermore, the 1995 Congress was responsive to subnational governments’ complaints about the burden imposed by mandates and enacted the Unfunded Mandates Reform Act of 1995, establishing new mandatory congressional procedures for the enactment of statutes imposing mandates.

States do not always oppose the total or partial loss of a regulatory power because they have been unable through interstate cooperation to solve a major problem, and in a few instances states have urged Congress to enact a preemption statute. An example of such a problem involved commercial truck drivers who held an operating license from each of several states. If such a driver had his or her license revoked or suspended for a serious motor vehicle violation, the individual often would continue to drive using a license issued by a second state. This practice was ended by a provision in the Commercial Motor Vehicle Safety Act of 1986, which made it a federal crime for a commercial vehicle driver to hold more than one operator license.

The enactment of numerous congressional preemption statutes has resulted in states losing a significant portion of their reserved regulatory powers. Nevertheless, it is important to note preemption statutes have encouraged states to employ powers previously unexercised or exercised to a very limited extent. Minimum standards preemption statutes in particular offer strong encouragement to state legislatures to exercise more fully their reserved regulatory powers and to set higher standards if they wish.

Congressional preemption statutes on occasion are designed to encourage states to enter into interstate compacts or to enact harmonious regulatory statutes in a given field. The Low-Level Radioactive Waste Policy Act of 1980 encourages states to enter into compacts for the disposal of such wastes, and ten such compacts, involving 44 states, have been established. The Atlantic Striped Bass Conservation Act Amendments of 1986 is unusual in supporting the enforcement of conservation plans drafted by the Atlantic States Marine Fisheries Commission, a interstate compact–created body with no enforcement powers. The act directs the U.S. Fish and Wildlife Service to impose a striped bass fishing moratorium on any state failing to comply with the plans.

An unusual opt-out provision is included in the Riegel-Neal Interstate Banking and Efficiency Act of 1994, permitting a state legislature to enact a statute forbidding interstate branching within the state that otherwise is authorized by the act.

The Gramm-Leach-Bliley Financial Reorganization Act of 1999 threatened to establish a national licensing system for insurance agents if 26 states did not adopt a uniform licensing system by November 12, 2002. The National Association of Insurance Commissioners on September 10, 2003, certified 35 states as having a uniform system on September 10, 2002, and preemption was avoided.

Congress decided it was essential to have a uniform digital signature throughout the nation and enacted the Electronic Signatures in Global and National Commerce Act of 2000, preempting the digital signature laws of 44 states. The act, however, exempts from preemption a state law adopting the Uniform Electronic Transactions Act drafted in 1999 by the National Conference of Commissioners on Uniform Laws.

Technological developments, such as telemedicine, and lobbying by interest groups ensure that Congress will continue to enact complete and partial preemption statutes altering the respective federal and state spheres of regulatory authority.

SEE ALSO: Burbank v. Lockheed Air TerminalCommerce among the StatesCooley v. Board of WardensHines v. DavidowitzPennsylvania v. NelsonSouthern Railway Company v. ReidSupremacy Clause: Article VI, Clause 2


Federal Statutory Preemption of State and Local Authority: History, Inventory, and Issues (Washington, DC: U.S. Advisory Commission on Intergovernmental Relations, 1992); Stephen A. Gardbaum, “The Nature of Preemption,” Cornell Law Review 79 (May 1994): 767–815; Joseph F. Zimmerman, Contemporary American Federalism: The Growth of National Power (Leicester, UK: Leicester University Press, 1992); and Joseph F. Zimmerman, Federal Preemption: The Silent Revolution (Ames: Iowa State University Press, 1991).