As Americans, we like to pride ourselves with being very familiar with the provisions of our Constitution. But I bet you’ve never heard of the Tonnage Clause. This provision is tucked way down at the end of Article I § 10. It reads:
“No State shall, without the Consent of Congress, lay any Duty of Tonnage, keep Troops, or Ships of War in time of Peace, enter into any Agreement or Compact with another State, or with a foreign Power, or engage in War, unless actually invaded, or in such imminent Danger as will not admit of delay.”
So what is this “duty of tonnage?” Believe it or not, the Supreme Court has dealt with the interpretation of this clause in a recent case, Polar Tankers v. City of Valdez (2009). This case, which also raised Due Process and Commerce Clause questions, represents another way in which the Founders used Article I to rein in attempts by the states to use taxation as a way to burden interstate commerce.
Although the Court did not reach the Commerce Clause question, it is clear that the operation of the Tonnage Clause is to keep states from burdening interstate commerce.
Paper Topic #22: Is the Tonnage Clause an historical artifact? Does it simply replicate the Commerce Clause, or does it add something unique to the contours of Article I’s distribution of economic power among levels of government?
Suggested Reading: Jensen, E. M. (2010). Quirky Constitutional Provisions Matter: The Tonnage Clause, Polar Tankers, and State Taxation of Commerce. Geo. Mason L. Rev.,18, 669.