Trade can benefit both sides even if one country is worse at literally everything

In 1817, David Ricardo showed that even if one country is more efficient at producing every good than another, both still gain from trade — each should specialize in whatever it's relatively least bad at, not what it's best at in absolute terms. The insight, called comparative advantage, remains the core argument for free trade in economics today.

— David Ricardo, On the Principles of Political Economy and Taxation — 1817
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