The Doctrine of Preemption addresses the question of what happens when state laws conflict with federal laws. In order to understand the Doctrine of Preemption, you must understand Article VI of the United States Constitution, also known as the “Supremacy Clause.”

The Supremacy Clause essentially states that federal law is the “supreme law of the land.” This means that the courts in every state must follow the Constitution, laws, and treaties of the federal government as the supreme law of the land.

The Doctrine of Preemption is based on the Supremacy Clause. The Doctrine essentially states that if a federal law preempts state law, then the state law is declared invalid. Therefore, a federal court may require a state to refrain from enforcing a law if the behavior conflicts with federal law.

However, absent a conflicting federal law, the court should enforce the state law. Further, if a state law provides more protections for consumers, employees, and other residents than existing federal law, then the state law will stand and be enforced.

What is Express Preemption and Implied Preemption?

In 1819 in the case of McCulloch v. Maryland, the United States Supreme Court Chief Justice John Marshall stated that “States have no power, by taxation or otherwise, to retard, impede, burden, or in any manner control the operations of the Constitutional laws enacted by Congress to carry into execution the powers vested in the Federal Government.” This statement was the cause of numerous cases regarding federal preemption of state laws.

However, some federal preemption cases were easier than others, as some laws stated that federal law was supreme on a matter, while others did not. Thus, two categories of federal preemption exist: express preemption and implied preemption. Additionally, implied preemption is further split into two categories: conflict preemption and field preemption.

Express preemption occurs when Congress explicitly states within a statute that the state law will be preempted. Simply put, when Congress explicitly states that federal law is the exclusive law, then states cannot interfere with that federal law.

Express preemption cases tend to be simpler than implied preemption cases. This is because the courts typically analyze the plain meaning of the statute drafted by Congress and Congress’ intent in enacting the statute.

Coincidentally, implied preemption occurs when Congress does not explicitly state that a statute is intended to preempt state law. In these cases, the federal statute may silent as to whether it preempts state law, may be ambiguous as to whether it preempts state law, or may raise questions as to whether state law and federal law work together.

However, the Supreme Court concluded that it is inferred that federal law does preempt if the law falls into the subcategories of implied preemption: conflict preemption or field preemption.  The subcategories of implied preemption are defined as follows:

• Conflict Preemption: Conflict preemption occurs when a state law directly conflicts with a valid federal law, making it either impossible to comply with both or the state law stands as a great obstacle to accomplishing the objectives of Congress. In essence, if a state law obviously conflicts with federal law, than the state law is automatically struck down or preempted.
• Field Preemption: Field preemption occurs when Congress substantially occupies a field of regulation, precluding any state regulation from entering the field. To clarify, think of a house that has rules, and a stranger comes over to visit and attempts to change those rules, but they are not allowed to do so because it is not their house. Thus, even if state law does not directly conflict with federal law, it can still be struck down or preempted if Congress has occupied the field with federal legislation.

  • Nuclear power is a common example of where the federal government substantially occupies a field. The Commerce Clause of the United States Constitution and the federal government’s dominance in the field of environmental law has resulted in field preemption of any state and local laws that interfere with federal environmental laws.
  • Congress’ occupation of the field of fishing is another example. Congress so heavily occupies the field of ocean fishing, that any state or local laws that frustrate the purpose of the national standards for fishery management will be struck down. This is so, even though Congress never explicitly states as much in the statutes themselves.

Does Preemption Exist at the State Level?

Similar to how federal law is superior to state law, state law is superior to local laws. Typically, preemption at the state level follows the process of field preemption, but varies based on the state’s constitution.

When the state legislature enacts legislation and the intent in doing so is to occupy that field, then local municipalities will be preempted from enacting their own legislation within that field. A recent example of this would be states that have legalized medicinal and recreational marijuana occupying the field, and preempting local laws from regulating outside the field.

Another example is, if a state legislature enacts gun control laws and their intent in doing so is to occupy the field of gun control, than local laws governing gun control will be preempted and deemed invalid.

Should I Hire an Attorney if I Need Assistance with the Doctrine of Preemption?

If you are involved in a case where you believe that your constitutional rights have been violated due to the Doctrine of Preemption, you should absolutely seek out a well qualified and knowledgeable government lawyer. When the Doctrine is involved with a lawsuit, that implicates certain state and local laws, it is important to first check the possible applicability of preemption.

Remember, the Doctrine can apply at time even when there appears to be no explicit conflict with federal law. Field preemption is a powerful tool that an experienced attorney may use to assist you. The guidance of an attorney is extremely beneficial when challenging state and local laws that appear to be less favorable than existing federal laws within the same field.