Back to economics 101: How Trump's tariffs disrupt 200 years of trade rules

Subscribe to enjoy similar stories. On 2 April, President Donald Trump didn’t just shock the world with his reciprocal tariffs announcement—he also upended 200 years of trade wisdom. Most of us take free trade and global supply chains as natural and necessary, but few realize these systems stem from the Law of Comparative Advantage, proposed by British political economist David Ricardo in 1817.

It’s worth revisiting what Ricardo argued, why it has worked (so far), and why it matters now. Read this | Are Trump’s tariff rates made up? Here’s how they may have been calculated Simply put, the theory suggests that individuals and nations should specialize in what they do best relative to others. This principle applies to daily life as much as it does to global trade.

For instance, take two flatmates, A and B, who want to divide household chores fairly. A takes one hour to cook and two hours to clean, while B takes two hours to cook and three to clean. A is faster at both tasks, giving her an absolute advantage.

But when deciding who should do what, comparative advantage comes into play. B is only 50% slower at cleaning but twice as slow at cooking, making cleaning the better task for B while A focuses on cooking. Daily decisions often follow this logic.

A highly paid executive might hire a driver—not because she can’t drive, but because her time is better spent reading or working during her commute. A homemaker might employ domestic help to focus on childcare, improving family well-being. The cost of hiring a driver isn’t just his salary but the productivity gained by the executive.