Historical perspectives and theories of international trade

1. Meaning of international trade

International trade is the exchange of goods, services, capital and technology across national frontiers. It differs from domestic trade in four ways that explain why a separate body of law is needed: the parties are subject to different legal systems, payment is in different currencies, the goods cross customs frontiers and are taxed there, and the transaction depends on carriers, insurers and banks in several countries. The law of international trade has two layers: a public layer of treaties between States (GATT, the WTO agreements, investment treaties) and a private layer governing the contracts between traders (sale, carriage, insurance, payment).

2. Historical background

• Ancient and medieval trade. Trade moved along the Silk Route linking China, India, Persia and the Mediterranean, and across the Indian Ocean, where Indian textiles, spices and gems were carried to Arabia, East Africa and Rome. Merchants developed their own customs on sale, carriage and bills of exchange, enforced in fair and port courts. This body of merchant custom, the lex mercatoria or law merchant, is the ancestor of the modern law of negotiable instruments, bills of lading and marine insurance.
• The age of chartered companies (16th to 18th century). European States treated trade as an instrument of national power. Trade was organised through monopolies such as the English East India Company (1600) and the Dutch East India Company (1602). Colonies supplied raw materials and bought manufactures. This is the period of mercantilism.
• The free-trade era (19th century). Britain repealed the Corn Laws in 1846, and the Cobden-Chevalier Treaty of 1860 between Britain and France contained an unconditional most-favoured-nation clause that spread through a network of European treaties. For India the period meant the export of raw cotton and indigo and the import of British machine-made cloth.
• Protectionism between the wars. After the First World War, States raised tariffs and imposed quotas. The United States Smoot-Hawley Tariff Act, 1930 provoked retaliation, and world trade shrank sharply during the Great Depression. The lesson drawn was that trade needed an agreed set of rules.
• The post-war order. The Bretton Woods Conference (1944) created the International Monetary Fund and the International Bank for Reconstruction and Development (World Bank). The planned International Trade Organization under the Havana Charter (1948) failed, but the General Agreement on Tariffs and Trade, 1947 was applied provisionally from 1 January 1948 by 23 original contracting parties, India among them. Eight rounds of negotiation followed, ending with the Uruguay Round and the establishment of the World Trade Organization on 1 January 1995. UNCTAD (1964) and UNCITRAL (1966) were set up within the United Nations system to speak for developing countries and to harmonise private trade law respectively.

3. Mercantilism

Mercantilist writers such as Thomas Mun (England's Treasure by Forraign Trade, published 1664) held that a nation's wealth lay in its stock of gold and silver. A country should therefore export more than it imports, earn a favourable balance of trade, and use tariffs, export bounties and colonial monopolies to secure it. Trade was seen as a contest in which one nation's gain was another's loss. The theory explains the navigation laws and colonial trade monopolies of the period, and it survives in modern arguments for trade surpluses and import substitution.

4. Absolute advantage: Adam Smith

Adam Smith attacked mercantilism in An Inquiry into the Nature and Causes of the Wealth of Nations (1776). Wealth consists in goods and the capacity to produce them, not in bullion. A country has an absolute advantage in a commodity when it can produce it with less labour than another country. If each country specialises in the goods in which it has an absolute advantage and trades for the rest, total output rises and both gain. Smith's illustration was that Scotland could grow grapes in hothouses, but at thirty times the cost of buying wine abroad.

Significance. The theory established that trade is not a zero-sum game, that specialisation and the division of labour increase world output, and that tariffs and monopolies reduce national welfare. It is the intellectual basis of free trade and so of GATT. Its weakness is that it cannot explain trade where one country is more efficient in everything.

5. Comparative advantage: David Ricardo

David Ricardo, in On the Principles of Political Economy and Taxation (1817), answered that weakness. Even if Portugal produces both wine and cloth with less labour than England, both gain if Portugal specialises in the good in which its advantage is greater (wine) and England in the good in which its disadvantage is smaller (cloth). What matters is the opportunity cost of one good in terms of the other. Comparative advantage remains the standard economic justification for trade liberalisation and for the WTO's rules against protection. Its assumptions (labour as the only factor, full employment, no transport costs, immobile factors) are its known limits.

6. Later theories

• Heckscher-Ohlin (factor endowment) theory. Eli Heckscher (1919) and Bertil Ohlin (1933) explained comparative advantage by differences in factor endowments: a country exports goods that use intensively the factor it has in abundance. Labour-rich India exports labour-intensive goods; capital-rich countries export capital-intensive goods. Wassily Leontief's study (1953) found United States exports to be more labour-intensive than its imports, the Leontief paradox.
• Product life-cycle theory. Raymond Vernon (1966): a new product is first made and exported by the innovating country; as it matures and standardises, production moves to lower-cost countries, which in turn export it back.
• New trade theory. Paul Krugman and others showed that economies of scale and consumer preference for variety explain much trade between similar industrial countries.
• Competitive advantage: Michael Porter. In The Competitive Advantage of Nations (1990) Porter argued that advantage is created, not inherited. A nation's firms succeed internationally where four conditions, the diamond, are favourable: (i) factor conditions, including skilled labour and infrastructure; (ii) demand conditions, a demanding home market; (iii) related and supporting industries organised in clusters; and (iv) firm strategy, structure and rivalry, strong domestic competition. Chance and government act on the diamond from outside. Its significance for policy is that governments should invest in skills, clusters and competition rather than in subsidies and tariffs. The Indian software industry around Bengaluru is the usual illustration.

How this is examined

As an essay: “Discuss the historical background of international trade” (January 2026), “Explain the significance of the absolute advantage trade theory” (June 2025), and “Explain the competitive advantage theory and its significance” (August 2024). For the history question, use the five stages in section 2 and end with GATT and the WTO, which leads naturally into the rest of the unit. For a theory question, give the author and book, the core proposition, an illustration, its significance for trade law (the case for liberalisation) and its limits. A paragraph on how the theory supports or departs from free trade earns the marks for “significance”.