I dimly recall learning that the point of the second paragraph of Article 1, Section 10 of the U.S. Constitution was to avoid ruinous trade competition among the states:
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 it’s 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 Controul of the Congress.
Any remotely modern conception of trade competition includes non-tariff barriers.* To what extent have U.S. states and localities been prohibited from implementing such barriers, and why hasn’t civic extortion — large businesses negotiating with several jurisdictions for ever larger public subsidy — been outlawed?
Of course I’m thinking of the professional sports racket. Another example in today’s media: $285m public subsidy for Detroit pro sports teams, while the city is bankrupt. But there’s also a probably much larger practice of states and localities goaded to offer huge subsidies to businesses in order to move their headquarters or other facilities. Sometimes only a matter of blocks, as in the case of Kansas-Missouri competition in the Kansas City metro area. What could be more clearly negative sum?
*Internationally, non-tariff barrier removal by treaty and other negotiation is often cover for spreading other anti-competitive and inequality promoting practices. I’m not a fan, especially considering that non-treaty autonomous liberalization has for decades been the main source of trade barrier reduction. I’m amused that contributors to the English Wikipedia article on non-tariff barriers to trade have listed “Intellectual property laws (patents, copyrights)” as examples of such barriers. This should be taken literally.