All it would take is the political will to tax remittances to Mexico, and use his position as Commander in Chief to order the military to do the building (since they are being paid no matter what duties they are performing).
Apparently the state department has $8B bucks just laying around to give away to 3rd world countries.
I know what it will take. I know how to do it. I’m just saying, it won’t get done. Just a prediction.