The wall must have a solid component PLUS a manned component.
The walls should be constructed with seismic tunnel busters.
The wall must have a solid component PLUS a manned component.
Agreed. But they also need to equip all the American citizen landowners all along the border with military grade commo equipment and give them specific call signs and frequencies so that they can directly contact a FAC (Forward Air Controller USAF) designated just for them that will be comprised of an Apache and scout teams capable of operating 24/7 365. Just in case the landowners come under threat (as has been the case for the last 25 years) by smugglers and invading migrants crossing their lands.
The entire wall should be preceded by a razor wire topped pair of fences as is the case in Spain which will be patrolled by teams with night vision and dogs. THEN the WALL. The wall should be thick enough so that it acts as a barracks in certain areas complete with detention areas to hold invaders, plus sleeping/eating and recreational areas for the staff that will be stationed there, probably the US Military.
At least that is the duty that the Constitution of the United States specifically assigns the armed forces.