It’s a start.
If Mexico refuses to pay, then we deny the equivalent amount of Mexican business.
Pretty soon, Mexico will make attempts to stop migration here and may even build their own fence to keep their economy flowing
All Trump really has to do is threaten to stop the one way Western Union telegraphing of money from here to Mexico. That’s about 40% of Mehico’s GDP.
There is an easier solution.
If you have been to the sanctuary cities, or any immigrant heavy location, there are money transfer services everywhere. Check cashing, wire transfers. Just tax each and every wire transfer out of the U.S. to Illegal immigrant source countries 75-85%. That will stop the cash cow handout, and catching smugglers with cash going out of the country where penalty is 100% forfeiture of funds will make them squeal.
Make them smuggle their money back to Mexico, not just go to Kroger and wire it to la familia.