Political philosophers tend to notice their differences more than their similarities. I suggest that contemporary analytic political philosophy in fact exhibits a 'dominant paradigm', the main features of which are a commitment to liberal capitalism and a preference for the designing of 'just institutions.' To subscribe to this paradigm involves making a decision about how to manage the philosophical 'agenda.' In order to focus on certain issues within this paradigm, alternatives, most notably socialism, have to be excluded from prolonged consideration. A popular way of supporting this policy is by reference to the perceived failure of 'real existing socialism.' Taking the late political philosopher Brian Barry, among others, as an example, I argue that this argumentative strategy is unconvincing, and furthermore that its deployment tells a worrying story about the practice of political philosophy.