Traditionally, it treats mostly the relations between national states, but larger states, International Organizations and non-state actors on the international arena, like non-governmental organizations, and multinational corporations are also considered in the sphere of International Relations.
According to US scholars, there are two main approaches to the field of International Relations. The first is the "Realist" or "Pragmatist" approach. This claims that conflict is inevitable and that the best way to approach international relations is to be prepared to engage in conflicts – and win.
The second approach is the "Structuralist" approach and is typified by diplomacy, according to which conflict is not inevitable, focusing the causes of conflict, stressing the costs of conflict compared to possible gains. This thinking has been heavily influenced by Galtung's theory of structural violence.
Broadly speaking the two approaches to International Relations can be attributed to either side of the Atlantic: Realism is seen as a primarily American worldview while Structuralism is seen as typically European. This differentiation, however, is chiefly confined to the academic world as many states seem to follow a Realist approach.