I am by no means an economics expert, but it seems to me that an import tax on Mexican goods would mean the US citizens buying the items would pay for the wall? Because the tax wouldn’t be absorbed by the company manufacturing the item, but they would add it onto the cost of the item.
In other words, if my item price is currently $10 and you’re going to charge me $2 to sell to the US, then I’m going to raise my price to $12 so that I still get $10 in my pocket.
That’s why there needs to be a tax on the money orders sent back to Mexico.
The company would have to be competitive so would probably swallow a good part of the tax to do so. If not, folks would look elsewhere for the product.......