section_path: Theories of motivation/Political science/System-level
section_name: System-level
paragraph_text: System-level
  
  There are several different international relations theory schools. Supporters of realism in international relations argue that the motivation of states is the quest for security, and conflicts can arise from the inability to distinguish defense from offense, which is called the security dilemma.
  
  Within the realist school as represented by scholars such as Henry Kissinger and Hans Morgenthau, and the neorealist school represented by scholars such as Kenneth Waltz and John Mearsheimer, two main sub-theories are:
  
  The two theories are not mutually exclusive and may be used to explain disparate events according to the circumstance. Liberalism as it relates to international relations emphasizes factors such as trade, and its role in disincentivizing conflict which will damage economic relations. Critics respond that military force may sometimes be at least as effective as trade at achieving economic benefits, especially historically if not as much today. Furthermore, trade relations which result in a high level of dependency may escalate tensions and lead to conflict. Empirical data on the relationship of trade to peace are mixed, and moreover, some evidence suggests countries at war do not necessarily trade less with each other.