Article I, Section 9, Clause 5: “No Tax or Duty shall be laid on Articles exported from any State.”
None ever has been.
For some obscure reason lots of the CSA apologist types have an impression that southern exports were taxed at extortionist rate. The actual fact, of course, is they were never taxed at all.
Just don’t try telling that to GT1945 cuz he’s done his reading and his research LOL