With President Trump threatening large-scale trade wars against multiple trading partners simultaneously, it’s time to explain, in terms of cause and effect, just why trade wars are terrible for the United States and world economies. With such threats, Trump risks plunging the whole world into a depression.

The entire global economy is integrated. With modern communications and rapid transport options, it cannot be otherwise. Goods and services, both raw materials and manufactured, flow across borders and become essential components of other goods and services, in an almost seamless web. The United States can no more be both self-sustaining and economically vibrant than it can fly its entire territory to the moon.