Under U.S. President Donald Trump, the world has taken a sharp turn back toward the 17th century doctrine of mercantilism — the notion that trade is a zero-sum game in which countries should be self-sufficient and focus on exporting far more than they import.

It worked for Louis XIV and other early European empires, and the aim of America First is to reintroduce it with the U.S. this time the victor.

Adam Smith developed the doctrine of free markets in response. To quote George Magnus of Oxford University’s China Center, he "saw the emphasis of mercantilism on the acquisition of gold and silver, and the associated suppression of imports and promotion of exports, as incompatible with the accumulation of wealth for citizens.”