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The Supremacy Clause and the Doctrine of Preemption

What happens when state law conflicts with federal law? The answer lies in a doctrine known as federal preemption. Generally, the preemption doctrine states that when a federal law conflicts with state law, the federal law prevails. While states may make their own laws, they must meet or exceed the federal standard.

The supremacy clause is in Article VI of the U.S. Constitution. Article VI says federal law is the "supreme law of the land." This clause means that judges in every state must follow the federal government's Constitution, federal laws, and treaties in matters directly or indirectly within the government's control.

The preemption doctrine comes from the supremacy clause. It states that federal law preempts state law when the laws conflict. Federal law also preempts state or local law if Congress intends to regulate an area and exclude the states. But case law involving federal preemption of state laws has shown that federal law should not preempt state law "unless that was the clear and manifest purpose of Congress" (Wyeth v. Levine).

In the absence of a federal law, that state law controls. Generally speaking, state regulations may provide more protection for people than federal law allows.

But, not all federal agency regulations preempt state regulations. As noted in the Supreme Court case Cipollone v. Liggett Group (1992), a presumption against preemption invokes federalism and state sovereignty principles. This presumption applies in all preemption cases (Altria Group Inc. v. Good).

Federalism and Enumerated Federal Powers

Under the supremacy clause, the federal government has broad powers to create, regulate, and enforce the laws of the United States. The concept of federalism, or federal power, has a long history dating back to the late 1700s when the U.S. ratified the Constitution.

In any preemption case, the analysis begins with the Constitution. The first question is whether the Constitution either expressly or implicitly preempts a state law. Another important factor that courts consider is Congress' intent when passing the federal law (Medtronic Inc. v. Lohr).

Express Preemption

The federal government has certain express or "enumerated" powers specifically spelled out in the Constitution. Article I, Section 8 contains these powers. Examples of express powers include:

  • The power to regulate commerce (the Commerce Clause)
  • The power to declare war and raise armies
  • The power to make laws, such as immigration or bankruptcy laws, necessary to execute the government's power

When a federal statute or federal regulation expressly conflicts with a state law, the federal law or regulation will generally prevail. Some federal laws contain an express preemption clause. A preemption provision indicates the legislative branch had preemptive intent with the federal law or regulation. This congressional intent will preempt conflicting state laws.

Implied Preemption

The federal government has express powers and implied powers under the Constitution. Implied powers are not explicitly expressed in the Constitution. But, the government argues these implied powers come from the necessary and proper clause of the Constitution. This was the decision in the landmark Supreme Court case of McCulloch v. Maryland (1819). Examples of implied powers include:

There are two types of implied preemption. Field preemption is when the federal government determines it occupies an entire field of regulation. In Arizona v. Inter Tribal Council of Arizona (2013), the Supreme Court considered an Arizona state law that required voters to provide proof of citizenship to vote in a federal election. The Supreme Court held that the National Voter Registration Act trumped the state law. The case stands for the idea that voter registration is an area the federal government controls.

Field preemption also applies to several instances in which the government has determined it has occupation of the field, including:

The second type of implied preemption is conflict preemption. In Gade v. National Solid Wastes Management Association (1992), the Supreme Court determined that federal law preempts a state law that conflicts with federal law. Specifically, the court held that federal Occupational Safety and Health Administration (OSHA) regulations preempted Illinois laws on workers handling hazardous material.

Conflict preemption applies to several areas of law, including:

  • Drug manufacturers, drug administration, and drug labeling — e.g., the Food and Drug Administration's (FDA) federal regulatory schemes may preempt state court decisions on drug labeling
  • Foreign sanctions
  • Automobile safety regulations, such as minimum safety standards

Whether express or implied, federal law will almost always prevail when it interferes or conflicts with state law. Unless the U.S. Supreme Court declares the federal law unconstitutional, or in situations where the supremacy clause does not apply, federal law will likely prevail. So, a federal court may prevent a state from enforcing a preempted state law.

But plenty of examples exist where tension between state and federal law remains unresolved. For instance, several states have legalized medical and recreational use of cannabis. Federal law deems cannabis a Schedule I controlled substance under federal law. The federal government, as of May 2024, is taking steps to reclassify cannabis as a Schedule II drug. In this case, it's mostly a matter of political will and resource allocation.

To that end, people in the United States should know about the federal government's broad powers. These issues include:

constitutional law attorney can help construe and interpret federal law as applied to a particular state law.

Examples of the Supremacy Clause: State vs. Federal Law

Example 1

Suppose Pennsylvania enacts a law that says: "No citizen may sell blue soda anywhere in the state." But, in this scenario, the federal government has already established the "Anti-Blue Sales Discrimination Act." This fictitious federal law bans actions that discriminate against goods sold based on color. A local food and beverage vendor who sells blue soda in vending machines gets charged with violating state law. The owner may challenge the state law because federal law preempts it. So, the vendor argues, the Pennsylvania law violates the supremacy clause of the U.S. Constitution.

Example 2

Fictitious Company hires you as a non-exempt, full-time employee. Your state has set a minimum wage of $5 per hour, and the company declares this is your pay rate. But, the federal minimum wage is $7.25 per hour. Under federal law, Fictitious Company must pay you at least $7.25 per hour. The federal law will supersede the state's minimum wage.

Get Professional Help With Your Legal Matter Today

If you have questions about whether a federal law preempts a state law, consider contacting an attorney. An experienced constitutional law attorney can give you more information about:

  • Whether federal law preempts the subject matter of a state tort law or a state authority's regulation
  • Whether a federal statutory scheme preempts a common law action
  • General information about constitutional law

Representing yourself in a legal matter can be very complicated. Contact a constitutional law attorney for help. An attorney can help protect your rights and offer sound legal advice.

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