At the time of Smith, Ricardo and Hecksher-Ohlin, businesses were generally small and most international trade was made in agricultural or mineral products or in small production. However, until 1947, the large industry had evolved and much of the trade was manufactured.  See z.B., ibid., 54: « The comparative advantage theory assumes that trade is balanced (i.e. exports of imports of equal value) and that work is fully occupied. If trade is not balanced, the surplus country must export certain products for which it has no « real » comparative advantage. A second extremely important reserve is the so-called factor price adjustment rate, which states that international trade will compensate for relative factors of production. B such as unskilled labour, between countries under free trade conditions. This would mean that for a high-wage country such as the United States, wages for unskilled workers would fall, while wages would rise in labour countries. However, factor prices will not tend to offset in sectors where production costs are falling. Western economic theory has also changed in recent years to reflect the fact that, since the early 1970s, world trade has grown much faster than overall economic growth. In 1973, the share of exports to GDP in the United States was 4.9%, up from more than double in 2005 to 10.2%. Globally, the rate was 10.5% in 1973 and 20.5% in 2005. Economists have had a huge impact on trade policy and provide a strong justification for free trade and the removal of trade barriers.
Although the objective of a trade agreement is trade liberalization, the actual provisions are strongly influenced by national and international political realities. The world has changed enormously since David Ricardo proposed the Law of Comparative Advantage, and in recent decades economists have changed their theories to take into account the trade in factors of production such as capital and labour, the growth of supply chains, which now dominate much of world trade, and the success of neo-travelist countries in achieving rapid growth. However, economic theory has evolved considerably since the days of Adam Smith and has evolved rapidly since the creation of the GATT. To understand U.S. trade agreements and how they should proceed in the future, it is important to review economic theory and see how it has developed and where it is today. In this world, the classic Ricardian trading model has provided a good explanation for business models such as product producing countries such as. B which countries would produce these products. England would produce textiles on the basis of its wool production and capital availability, and Portugal would produce wine on the basis of its sun and fertile soil. If Portugal decided to create barriers to imports of British textiles, its economy would be weaker and it would still be in Britain`s interest to allow the free importation of Portuguese wine.