Abstract
Shhh! If you keep very, very quiet, and listen really, really carefully, you just might hear it rustling around underneath the Constitution. Like the sound of a tree falling in a deserted forest, constitutional law commentators are never sure if it truly exists. And, like people who claim to have seen UFOs, state governments swear that it exists and is here to conquer them. What is this lurking presence that so perplexes the mind? It is the doctrine of the dormant Commerce Clause, perhaps the Supreme Court's best known invocation of constitutional silence. And, to continue mixing metaphors, that unseen constitutional doctrine acts like a colorless, odorless toxic gas: a silent killer of state laws affecting interstate commerce.
Exactly what is this hideous thing? In short, the dormant Commerce Clause is a constitutional law doctrine that says Congress's power to "regulate Commerce among the several States" implicitly restricts state power over the same area. In general, the Commerce Clause places two main restrictions on state power. First, Congress can preempt state law merely by exercising its Commerce Clause power. Second, the Commerce Clause itself-absent action by Congress-restricts state power; the grant of federal power implies a corresponding restriction of state power. This second limitation has come to be known as the "dormant" Commerce Clause because it restricts state power even though Congress's commerce power lies dormant.