The Discipline of International Trade

International economics has distinguishing characteristics which make it a unique sub-field in economics. It is vitally concerned with the co-existence of markets with overlapping domains - some markets are national and some international, with different rules applicable to residents of different countries. This paper describes various ways in which these markets interact, and how such basic propositions as factor-price equalization emerge as core results of the theory. Countries wish to preserve some control over certain markets, e.g. labor markets and a variety of services. As a consequence, free trade in all markets is not "optimal", even for a small country.