The border wall does not need to go 2000 continuous miles. Probably 500 miles of wall in the places that are easiest to cross would deter most of the people just walking in. Some would come in through the gaps, but it should cut the numbers way down. Or maybe we need 750 miles of walls well placed in the most accessible areas. But it probably doesn’t need to be 2000 miles.
Anyway, build 500 miles in the areas with the heaviest illegal entry and then you can monitor where the leaks spring up, and go later and build more wall there, until the leaks are minimal.
I think tunneling will be more likely than people going a hundred miles out of their way to circumvent the wall. Some will, but not masses.
“I think tunneling will be more likely than people going a hundred miles out of their way”
Tunnels are not easy to make. They would have to be pretty long so the two ends weren’t near enough to the wall to be easily detected.
Tunneling under a wall is far more expensive than just walking over the non-existent border wall.
BS. The physiological boost in knowing the wall is contiguous is worth the cost. It sends a message. The wall is political as well as functional.