1. Bad wall. If you can't see the other side, it's easy to jump in and escape. Fences are better.
Step back 3 meters and build. Anyone who touches the fence can shoot, so no one dares to climb.
It doesn't matter if you dig a tunnel, unless you go back, you can only be caught.
4. Build a structure similar to Wengcheng, and keep the illegal people directly outside the fence, so that you have nowhere to escape.
5. Add some cameras, computer monitoring, partial discharge, underground vibration sensing sonar and so on. Management is also very economical and efficient, so smuggling is basically hopeless, and it is useless to come and get caught.
As a management tool in the United States, this has nothing to do with racism. Only a wall can legally enter the country. National boundaries are not the free world of the Internet, but need substantial isolation.