Tonnage Clause Law and Legal Definition

Tonnage clause is a clause in the U.S. Constitution that ensures federal primacy in regulating commerce. This clause restricts the states from imposing taxes on any shipment of cargo without the consent of Congress. The tonnage clause in the constitution reads: “No State shall, without the Consent of Congress, lay any Duty of Tonnage ****”. [USCS Const. Art. I, § 10, Cl 3]. This clause was ratified in 1787.