Trade across political boundaries should be taxed. Generally, the more significant the political boundary, the higher the tax rate (tariff). This tax wouldn’t apply to people who buy things within the same jurisdiction or who travel to one political jurisdiction and buy things within that same jurisdiction. It would only apply if the seller ships the item to the customer in a different jurisdiction. Trade across city boundaries would be lowest (perhaps 1%), counties would be higher (perhaps 3%). Interstate trade would be taxed at an even higher rate (perhaps 5%) while tariffs of at least 10% should be levied on all imported goods and services which cross an international border. These taxes would tend to prevent the formation of large super-efficient businesses which often gain very large portions of market share. These taxes would also make it easier for smaller, ‘mom-and-pop’ businesses to open up and succeed.
For countries with human trafficking or other forms of immoral behavior that is not tied to a specific product, import taxes (tariffs) should be levied on all imports from that country so that there is an effective economic incentive to cease such practices.