International relations focuses on world systems and the structures of international politics and policies. International relations promotes the understanding of certain theories of the functioning of the government of nations and states. International relations theories inform on the purposes, the resulting problems, the origin and development of international systems.
Realism contains many sub-categories such as classical realism, modern realism or neo-realism, and structural realism. Realism refers to "real life," weighing in the positive and negative values. As such, realism underlines issues such as the pain of war, the fragility of peace, the attempt at security and the threats to survival. Under the realist theory, the underlying motives include national interest, national security and personal/national power. The fundamental fields which contribute to this area include economics, history and political science.
Constructivism also centers on the problem of state identities, vested interests and their beginnings and implications. Constructed identity acts as the driving force of this concept, although precise reasons vary. This theory draws on the principles embedded in sociology, social psychology and cultural studies and views the social identity as bearing considerable influence in the material world.
Founded by Karl Marx, the Marxism doctrine stands as another international relations pillar with concerns rooted in the world problem of inequality, marginalization and exploitation. The key processes of Marxism include class conflict on the world scale, the class struggle, international divisions of labor, the challenge of an international capitalist system, and modes of production and trade.