several problems with this:
article 1 section 9 prohibits congress from laying a tax on exports from any state:
article 1 section 9:
No tax or duty shall be laid on articles exported from any state.
additionally there is this:
article 1 section 10 prohibits states from imposing taxes on imports or exports, except what is needed to fund its inspection laws. all revenue above this is to be paid the the us treasury.
article 1 section 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 on 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.
then again the buzzards in DC willfully ignore the constitution, except when its convenient for their agenda; so i guess it doesnt really matter.
edit to add:
since when does any tax go to its intended target(s) for very long? eventually the govt seizes it for itself for its own usage like making weapons of war and sending our troops into harms way for no good reason.