Article I, Section 9, Clause 5:
No Tax or Duty shall be laid on Articles exported from any State.
Article 1, Section 9, Clause 5 of the U.S. Constitution prohibits Congress from laying taxes and duties on articles exported from any state.
1Known as the Export Clause,
2 it applies to taxes and duties, not user fees.
3 The Supreme Court has interpreted the Export Clause to address shipments only to foreign countries, not shipments to unincorporated territories, such as Puerto Rico and the Commonwealth of the Northern Mariana Islands.
4
Footnote 4:
Jump to essay-4Dooley v. United States, 183 U.S. 151, 153–54 (1901);
see also Swan & Finch Co. v. United States, 190 U.S. 143, 144–45 (1903) (explaining 'export’ as used in the Constitution and laws of the United States, generally means the transportation of goods from this to a foreign country);
see generally Christina Duffy Burnett, United States: American Expansion and Territorial Deannexation, 72 U. Chi. L. Rev. 797, 800 (2005) (explaining the U.S. Supreme Court’s doctrine of territorial incorporation divided domestic territory . . . into two categories: those places ‘incorporated’ into the United States and forming an integral part thereof (including the states, the District of Columbia, and the ‘incorporated territories'); and those places not incorporated into the United States, but merely ‘belonging’ to it (which came to be known as the ‘unincorporated territories')).
constitution.congress.gov
That was my first thought too. I was incorrect.