19 U.S.C. § 1588

If any merchandise is laden at any port or place in the United States upon any vessel belonging wholly or in part to a subject of a foreign country, and is taken thence to a foreign port or place to be reladen and reshipped to any other port in the United States, either by the same or by another vessel, foreign or American, with intent to evade the provisions relating to the transportation of merchandise from one port or place of the United States to another port or place of the United States in a vessel belonging wholly or in part to a subject of any foreign power, the merchandise shall, on its arrival at such last-named port or place, be seized and forfeited to the United States, and the vessel shall pay a tonnage duty of 50 cents per net ton.