Through most of history communities imported only those goods they could not acquire or produce locally. According to this norm each meets its own needs as far as possible Closely related to these two norms for trade is the question: Who should make the decisions: communities or individual trading units? If communities, they tend to the former ideal; if the trading units, to the latter.
Third, if communities play a role in decision-making, what are these communities? In traditional societies they might be villages or towns; in the modern period, nation states.
Answers to these questions lead to two quite different models of trade. In one model, nations may be thought of as the units of trade. This is associated with support for domestic production even when goods could be imported more cheaply. Although it is rare that nation states, are the trading units, because they regulate trade according to their interests, we may speak of this system as "international trade".