A second core assumption of the neo-realist definition of power is that a ‘self-help’ world mean that state have to be worried about relative as well as absolute gains. In their 1980 debates with neo-Liberals, neo-realists were famously pessimistic about the prospects for lasting international co-operation for the reasons that, as Grieco (1988:487) put it: “states must give serious attention to the gains of partners” because they worry that today’s friend may be tomorrow’s enemy in war, and fear that achievements of joint gain that advantage a friend in the present might produce a more dangerous potential foe in the future.