ABSTRACT
This chapter considers how ideas about peace and war, about conflict and security, have changed over time. In considering changes in ideas about security over time, it begins with two classic international relations theories—one that focuses on the state, and another that focuses on varied interests. The chapter also considers the assumptions about key actors and the nature of the international order. State-based notions of security traditionally draw from one classical international relations theory: realism. In realism, the survival of the nation-state is its main goal, and this includes ensuring its stability and security. Security can best be ensured through power, which is expressed by military capability. The fundamental principle upon which collective security is founded provides that an attack on any one state will be regarded as an attack on all states. The idea of security has been stretched and pulled as our world faces new and complex crises.
