How smart would a 'smart wall' be?

Land such as this is not a likely candidate for President Donald Trump’s “big, beautiful wall.”

But it is fertile for an invisible kind of fence, one built of artificial intelligence, radar, drones, sensors, motion-activated cameras and even lidar, the same technology used in self-driving vehicles.

“Virtual walls” or “smart walls” along the southwest border are increasingly being billed as an alternative to the proposed concrete and steel barriers that have so sharply divided public opinion.

An electronic fence is not about preventing intrusion as much as it is about detecting intrusions and then intercepting them.