International relations is the study of relationships between nations. When analysing international relations three general levels refer the complexities of world politics: individual, state and the international system.
The individual level of analysis focuses on decisions made by individual people that go on to shape foreign policy. This type of analysis will involve examining the traits, desires and ideals of the individual, and the impact that they had on decisions that affected world politics.
The state level of analysis looks at the nature of the state and the impact it has on the way it behaves internationally. It analyses cultural influences, the state's geographical location and its historical legacy to explain how it acts internationally.
This level examines the international system to see how that influences the way in which a state acts; focusing on the way a state reacts to changing international influences. The most important factor here is how powerful the state is within the international system.