Federal Law as Law of the Land: Federal Preemption

by Samantha Bloch

The United States is a federal system in which federal laws and state laws coexist. But what happens when state law conflicts with federal law?

The short answer is that “state laws that conflict with federal law are ‘without effect’.” This is the doctrine known as federal preemption, which is based on the Supremacy Clause of the U.S. Constitution. This clause creates a hierarchy of laws in which the U.S. Constitution is at the top, followed by acts of Congress and ratified treaties, and ending with state laws. Its purpose is to ensure that states don’t pass laws that undermine the goals of the United States.  While a state could pass a law that conflicts with a ratified treaty, this blog post will focus only on conflicts between state and federal law.

The U.S. Constitution establishes a strict division of legislative authority between the federal government and the states in certain matters. For example, most foreign affairs issues and some aspects of the regulation of interstate commerce are reserved to Congress. Under the Tenth Amendment, powers not delegated to the federal government or prohibited to the states are reserved to the states. However, the U.S. Constitution also provides room for concurrent powers: legislative powers that both Congress and the states may exercise.

One such power, the power to tax, is usually not subject to federal preemption. For all other concurrent powers, if there is direct conflict between a state law and a federal law, courts will invalidate state law under the Supremacy Clause. But when exactly does a state law enter into direct conflict with a federal law?

The first element that needs to be present is a federal law regulating the activity that is the subject of the state law. The existence of such a law is, however, not enough. Courts pay particular attention to whether it was Congress’s purpose to supersede any conflicting state law. In the presence of concurrent powers, the Supremacy Clause does not limit the federal government’s power to preempt. But it is necessary for Congress to specifically exercise this power if it wants to effectively limit states’ legislative authority. A federal agency acting within the scope of the authority delegated to it by Congress also has the power to preempt state measures.

Two concepts are useful in determining the preemption purpose of a law or regulation: express preemption and implied preemption.

Express preemption is the most direct expression of Congress’s or an agency’s purpose. This form of preemption exists when a federal statute or regulation contains explicit language stating that it intends to preempt all state law regulating the activity that is the subject of the statute. The 2018 Restoring Internet Freedom Order issued by the Federal Communications Commission provides a recent example of an express preemption clause. It states that it “preempt[s] any state or local measure that would effectively impose rules or requirements that [it] has repealed or decided to refrain from imposing … or that would impose more stringent requirements for any aspect of broadband service that [it] addresses.” This renders all attempts by states to impose net neutrality obligations on internet service providers futile since the order would automatically trump any state measure attempting to impose additional or more rigorous requirements.

Implied preemption occurs when federal law does not explicitly state that it intends to preempt all conflicting state law but it is still possible to determine that Congress or an agency intended to preempt state law in that particular area. This is the case, for instance, when it is impossible to comply simultaneously with the federal law and the state law or when state law interferes with the objectives of the federal law. For example, a state cannot pass laws regulating air and water if they interfere with any goals or requirements established by existing federal environmental laws.

Implied preemption also includes the concept of field preemption. Field preemption exists when Congress has so broadly regulated a certain field of law that it implicitly must have chosen to prevent states from effectively legislating in that area. An example of this is U.S. immigration law, which is a field exclusively occupied by federal laws and regulations.

In an implied preemption analysis, courts presume that Congress intended to defer to states in matters of traditional state action. For example, when states are legislating, within their historic police powers, there is a presumption that Congress’s purpose was to not supersede state measures unless there is a clear and manifest purpose to the contrary. Therefore, a court will only invalidate a state law in a field traditionally occupied by state measures in the presence of an express preemption clause.

In the absence of federal law, or when Congress has not expressly or impliedly barred states from passing legislation to regulate certain activity and provide broader protections or benefits than what is available under existing federal law, state laws are usually valid. Except, of course, when they don’t comply with other constitutional obligations. In fact, the “dormant” Commerce Clause doctrine prevents states from passing measures that discriminate against or unduly burden interstate commerce, even in the absence of conflicting federal legislation. That, however, is a subject for an other blog post.