Article I.
Section 9.
Clause 5. No Tax or Duty shall be laid on Articles exported from any State.
Clause 10. No State shall, without the Consent of the Congress, lay any Imposts or Duties on Imports or Exports, except what may be absolutely necessary for executing its inspection Laws: and the net Produce of all Duties and Imposts, laid by any State in Imports or Exports, shall be for the Use of the Treasury of the United States; and all such Laws shall be subject to the Revision and Control of the Congress.
Well, I guess that pretty much blows that argument.
The current Congress is likely to consent to anything that will bring more revenue to the government.
(Thanks for looking it up.)