Why are we bothered by intervention? What kind of.a problem is intervention? Intervention involves altering the balance of power in a state. In order to differentiate intervention from a constant process of influence we need to develop a theory of intervention which distinguishes alteration from mere influence. Such a theory would demonstrate the various ways in which such alterations may be achieved and the conditions under which they are likely to occur. This is a process of building middle-range theories of international relations. But intervention also raises questions of a first-order kind which entail something more than middle-range theories.