How about Trump asks for contributions to build the wall? We appoint an accounting firm to handle all funds as opposed to the Gov. and the AFGE.
Towers, strategically placed, manned with smart technologically implemented .50 caliber fully auto machine guns.
On detection, first fires non lethal warning spray of copper jacketed lead projectiles. If ignored, instantaneously switches to lethal mode.
A few incidences may result in lower attempts of illegal border crossings.