Intro to LawWhat Law Is

Federal and State Law

Under the Supremacy Clause valid federal law overrides conflicting state law (preemption); otherwise states make most law, and each state has its own constitution, statutes and courts.

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The United States has two layers of government, as you saw in federalism. So every place in the country has two bodies of law at once: federal law and the law of its state. Most of the time they fit together. When they clash, the Constitution says which one wins, and how far that win reaches.

The Supremacy Clause, Article VI, Clause 2. Tap the marked phrases.

Key idea

Under the Supremacy Clause, a valid federal law overrides a conflicting state law. This is called preemption. Where there is no valid federal law or no conflict, state law governs, and states make most of the law people meet day to day.
  • Express preemption: Congress says in the statute that state laws on the subject are displaced.
  • Field preemption: federal regulation is so complete that Congress left no room for the states in that field.
  • Conflict preemption: it is impossible to obey both laws, or the state law stands as an obstacle to the federal law's purposes.

Why it works

The national government has only the powers the Constitution lists; the rest are reserved to the states (the Tenth Amendment). So supremacy has two built-in limits. First, a federal law must be valid: within Congress's powers and consistent with the Constitution. Second, there must be conflict or displacement. That is why criminal law, family law, property, contracts and torts are mostly state law, and why each state has its own constitution, statutes and courts. Each state's highest court has the last word on what its own state law means.

Worked example: Two minimum wages

The federal minimum wage is \$7.25 an hour. A state sets its minimum at \$15. An employer says federal law preempts the state law. Is the employer right?
  1. Is there a conflict? An employer can obey both by paying \$15, which is above \$7.25.
  2. The federal law sets a floor and does not say states may not go higher.
  3. No conflict and no displacement, so both apply.

Answer: No. The employer must pay the state's \$15.

Worked example: Impossible to obey both

A federal statute requires a warning label in exact federal wording and forbids changes. A state law requires a different warning on the same label. What happens?
  1. A maker cannot follow both: the federal law forbids the change the state requires.
  2. That is conflict preemption (and the statute may preempt expressly too).
  3. If the federal law is valid, the state requirement gives way.

Answer: The state requirement is preempted.

The same act can break both laws. Because the states and the nation are separate sovereigns, each may prosecute it under its own law without violating double jeopardy: the Supreme Court reaffirmed this "dual sovereignty" rule in Gamble v. United States (2019). And a state constitution can protect rights more broadly than the federal Constitution, as long as it does not take away federal rights.

Where most of the law on each subject comes from.

Common mistake

Thinking federal law beats state law in every case. Only valid federal law prevails, and only where it conflicts with state law or occupies the field. Ask two questions in order: (1) is the federal law within Congress's powers? (2) can a person obey both, and did Congress mean to displace state law? If the answer to (2) is "yes, both can be obeyed, and no displacement," both laws apply.
This is an educational course, not legal advice.

Practice

Pass with 3 right answers, the last 2 in a row. Each right answer earns 2 XP.

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