Neo-realism, also known as new realism or structural realism, is a theoretical framework in international relations that emphasizes the role of power and the constraints of the international system in shaping state behavior. Other synonyms for neo-realism include balance of power theory, which emphasizes the need for states to balance against each other to maintain stability; neoclassical realism, which incorporates the role of domestic factors such as leadership and bureaucratic politics in shaping foreign policy; and defensive realism, which posits that states primarily seek to maintain their own security rather than pursue expansionist ambitions. These varying perspectives on neo-realism reflect different interpretations of international relations and the role of power in shaping state behavior.