New Delhi, April 3 -- 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.

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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 ...