## TL;DR

International trade involves exchange of goods and services across borders. Comparative advantage (Ricardo, 1817): countries benefit by specializing in what they produce most efficiently, even if they're worse at everything. WTO (1995) governs trade rules. Protectionism: tariffs, quotas, subsidies to protect domestic industries.

## Core Explanation

Free trade agreements: NAFTA/USMCA, EU Single Market, CPTPP. Trade war: US-China (2018+, tariffs on $500B+ goods). Balance of trade: exports minus imports. Trade deficit: imports > exports — US runs persistent deficit. Supply chains: globalized production, just-in-time delivery, vulnerable to disruption (COVID, geopolitics). Currency exchange rates: affect trade competitiveness — weaker currency = cheaper exports.

## Further Reading

- [International Economics: Theory and Policy (Krugman, Obstfeld, Melitz)](https://www.pearson.com/en-us/subject-catalog/p/international-economics-theory-and-policy/P200000005849)