If federal law conflicts with state law, what is the result according to the U.S. Constitution?

• A. State law prevails
• B. The Constitution voids both
• C. Federal law prevails
• D. The matter is decided by the Supreme Court only

Answer: (C)

The central idea is that the Constitution places federal law above state law when they clash. The Supremacy Clause says that the Constitution, federal statutes made under its authority, and treaties are the supreme law of the land, binding on states and their courts. So, if there is a valid federal law that covers an issue, a state law that conflicts with that federal rule cannot stand; the state law is preempted to the extent of the inconsistency. This is known as preemption.

There are different ways preemption can manifest. Express preemption happens when a federal law explicitly says it overrides state law. Implied preemption can occur when federal regulation occupies a field so completely that states have no room to regulate there, or when it would be impossible to comply with both laws or the state law would obstruct the federal objectives. In those cases, the federal rule governs and the conflicting state rule must yield.

If there’s no conflict—either because federal law doesn’t address the issue or the state law can operate alongside federal rules without undermining them—state laws can still function. But in a real clash, federal law prevails.