"For five millennia, politicians have proposed walls like Trump’s. They don’t work."

In an op-ed in The Washington Post, anthropologist Adam Smith offers lessons from history on Donald Trump's proposed wall as a solution to border problems.

"Donald Trump’s proposal to build a wall along the border between the United States and Mexico to block the flow of migrants has been justly criticized on moral, economic and political grounds," writes Smith, Goldwin Smith Professor and chair of anthropology. "But while the Trump Wall (as he has called it) is the most provocative proposal of the election season, it is not particularly original. Over the past five millennia, politicians have repeatedly turned to large walls to solve problems. We should look carefully at the track record of this ancient technology before we invest what some estimates suggest could be $25 billion in construction costs for a 2,000-mile-long wall, plus millions more in annual maintenance."

The full op-ed appears in The Washington Post.