http://www.washingtontimes.com/news/2019/jan/13/democrats-now-back-george-w-bush-technological-wal/

The Department of Homeland Security spent seven years and more than $1 billion trying to create a wall of technology at the border or, as President George W. Bush called it, a "virtual fence." It was a bust.

Now the idea has returned as the main ante for congressional Democrats in the border security spending fight. Opposed to President Trump's physical barriers, they say drones, sensors and other electronics are all the tools needed a "technological wall," in the words of House Speaker Nancy Pelosi, California Democrat.