Walls. Big walls. 20' high and 5' wide, with electic fencing on top.
And let's make sure to award the building contract to a company that doesn't hire illegals! I'm just fed up with these lawbreakers...
The organizations that built the Israeli fence should be contracted ex post haste and dispatched to the Southern border.
Additionally, thick concrete walls needs to be sunk fairly deep into the earth to prevent "tunneling."
We are being invaded.