Theory and practice of intervention

The article discusses, first, systems control theory, which tells us how a self-regulating system, for example of social and political peace, should work. Second, it considers the theory of imperfect markets, which tells us just why peace and security frequently fail to be obtained. Third, it discusses collective action theory, which tells us what might be required for collective intervention in another state’s affairs to take place. These set the context, fourth, for a new idea – a theory of intervention – that might explain why individual states, rather than a collective of states, intervene or fail to intervene elsewhere. Fifth, to learn whether the practice of intervention appears to follow the theory laid out, descriptive evidence is presented for interventions undertaken by Australia, Canada, India, and New Zealand, 1899 to 2005.