When one state is completely dependent on another, it is the weaker which can call the tune: it can threaten to collapse unless supported, and its protector has no answering threat in return.
-- A.J.P. Taylor, The Struggle for Mastery in Europe: 1848-1918.
... Iraq being only the most recent example.
The pattern that Taylor describes is similar to that in the more famous Taylorism from The Origins of the Second World War: "The negotiations between Germany and the Allies became a competition in blackmail, sensational episodes in a gangster film. The Allies, or some of them, threatened to choke Germany to death; the Germans threatened to die."