There have been thousands of years of human history involving ever-changing waves of human immigration, shifting borders, rising and falling empires. In the past 2000 years I can think of very few successful Walls. (China, Hadrian's, Berlin spring to mind, but no others do...)
None of them lasted long, none of them were successful in stopping the flow of human history, but in their favour each has provided their country with a popular tourist attraction.
So, get in early, set up your tour company, and in say 20 years you could be running tours to view the "Trump Wall"... or what's left of it after it has been scavenged for shanty-town building...