If Trump and Republicans in general had any common sense, they would realize that the solution to the border situation is not a literal fence that can be breached, or tunneled under. Instead, they should be concentrating on technology that can do the job better.
The US is about to spend Billions on a wall, that once built will have to be repaired and maintained, and monitored - for how long?
There is already technology available that can sniff the air and find drugs, people and whatever it is tuned for in a given area. Lining the border with such technology and then having a ready force to go inspect hits is a much better way of "protecting" the border.
Here is an article that shows how technology can use dog like sensors to do the job.
https://phys.org/news/2016-12-scient...se-mimics.html
Unfortunately, too many people in this country don't believe in science. Many seem to think it is some kind of mysterious process and therefore unfathomable and akin to "witchcraft."
Just as unfortunately, the stupid are in control now, and wasting billions of dollars we don't have appeals to them. Why, I can't say - probably just goes back to them being stupid.