If for no other reason, history will remember the 2016 presidential election for Donald Trump’s campaign promise to build a wall across the entire Mexico–U.S. border. Set aside for a moment the rather vexing question of whether Trump will win the White House. Let’s focus on the pitch that could get him there: Could Trump in fact build a Great Wall of Making America Great Again?
As with so many things in this election, the question beggars belief. Trump is pledging the largest infrastructure project since the U.S. highway system—perhaps the most significant infrastructure project since the Erie Canal—and yet he has shared few details about the wall itself. What little Trump has said, namely that he intends for Mexico to pay for it, is unrealistic, to put it mildly.