Classical Realism is one of the oldest and most influential theories in International Politics. It views international relations through the lens of power and the inherent flaws of human nature.

Core Principles

• Human Nature: Realists believe humans are naturally selfish, power-seeking, and competitive.
• Power as the Central Concept: International politics is defined as a "struggle for power". States always seek to maintain or increase their power relative to others.
• National Interest: Politics is governed by objective laws rooted in human nature, and interest is defined in terms of power.
• State-Centricity: The sovereign state is the only significant actor in global politics.

Formula: International Politics = Struggle for Power among Nations.

Also known as Structural Realism, Neo-Realism shifts the focus from human nature to the structure of the international system.

Key Arguments by Kenneth Waltz

• Anarchy: The international system is "anarchic," meaning there is no central world government to enforce rules.
• Systemic Structure: The behavior of states is determined by the system's structure (specifically the distribution of power/capabilities) rather than the internal characteristics of states.
• Survival: The primary goal of every state is survival, which leads them to engage in "self-help" behaviors and balance of power.
• Distribution of Capabilities: States are distinguished by their power capabilities; the system's stability depends on whether it is unipolar, bipolar, or multipolar.

Liberalism challenges the realist view by emphasizing cooperation, ethics, and the role of non-state actors.

Core Principles

• Rationality and Progress: Human beings are rational and capable of learning to cooperate for mutual benefit.
• Democratic Peace Theory: Democracies are less likely to go to war with each other.
• Interdependence: Economic ties and trade between nations make war too costly and promote peace.
• International Law and Norms: States should follow moral principles and legal rules to ensure global order.

Neo-Liberalism, often associated with Liberal Institutionalism, focuses on how international institutions can facilitate cooperation despite an anarchic system.

Key Features

• Role of Institutions: International organizations (like the UN or WTO) help reduce uncertainty, prevent cheating, and provide a platform for negotiation.
• Absolute vs. Relative Gains: While realists worry about who gains more (relative gains), neo-liberals focus on whether everyone gains something (absolute gains).
• Complex Interdependence: States and non-state actors are linked through multiple channels, making military force less effective as a tool of policy.