Why Trump's wall with Mexico is so popular, and why it won't work

The United States already has about 650 miles of wall along the border with Mexico

Donald Trump tweeted on Jan. 6 that “any money spent on building the Great Wall (for the sake of speed), will be paid back by Mexico later.”

The dishonest media does not report that any money spent on building the Great Wall (for sake of speed), will be paid back by Mexico later!

— Donald J. Trump (@realDonaldTrump) January 6, 2017

The Economist reports that 40 countries have built fences since the fall of the Berlin Wall. Thirty of these were built since 9/11; 15 were built in 2015.

The United States already has about