U.S. Constitution, Article I — The Legislative Branch, Section 9, Clause 5
No Tax or Duty shall be laid on Articles exported from any State.
Notes
Bars any tax or duty laid on articles exported from any state. The prohibition applies to all goods leaving a state for export, and its text contains no exception, so neither a tax nor a duty may be placed on exports from any state for any purpose.
Use as reference
Lexinter.net | U.S. Const. art. I, § 9, cl. 5 | https://laws.lexinter.net/constitution/us/article-1/section-9/clause-5