You mean like the original income tax we had that has morphed into the monster it is today?
What makes you think the sales tax won't do exactly the same thing.
For one thing, there are many cities on the American/Mexican border. Alot of towns on the Mexican border already subsist by catering to American money (think Tijuana). Now, given this, and given the fact that in Mexico, everything is cheaper by default, the question soon comes.
If someone lives in say, El Paso, and they're saddled with the 23 percent national sales tax, and for the sake of argument (because I dont know what it actually is), Texas adds 6 percent.
So 29% sales tax. Now, let's say their is an item you want, and the exact identical item is sold in Ciudad Juarez. Same quality, same everything. And (this part is odd because Mexico is cheaper, but sake of argument) supposed, both items are valued at $100.
And let's suppose Mexico doesn't have a sales tax (once again, I don't go frequently enough to know if they do or not)
So, in both Ciudad Juarez and El Paso, you have the $100 item.
In El Paso, this item will cost $129 because of the sales tax, and in Ciudad Juarez, the item will cost $100.
Now tell me something, what do you think an El Pasoite would do in this situation. Stay in the good ole US of A and pay an extra $29, or, go shopping in Ciudad Juarez and get a great bargain.