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Game theoretic analysis of deterrence has been criticized for not capturing how actors realistically behave. It is alleged that prospect theoretical re-modeling provides a better foundation for a deterrence theory. The article analyzes how the strategies change when a prospect theoretical function is applied to a central deterrence game. While the probability distributions changes, it cannot alter the general dynamics. When considered together with previous research, it shows that prospect theory neither can or should replace standard assumptions when constructing a deterrence theory. However, viewed as a compliment, prospect theory expands the modeling possibilities and opens up for important new aspects.

Contemporary theories of deterrence place a strong emphasis on coherency between model and theory. Schelling’s contention of irrational threats for successful deterrence abandons the rationality assumption to explain how a player can deter, thereby departing from the standard game theoretic solution concepts. It is a misfit model in relation to a deterrence theory and, therefore, excluded. The article defends and remodels Schelling’s intuition by employing the level-k model. It is shown that an unsophisticated player that randomizes over its strategies brings about an advantageous outcome. The model also shows that the belief that a player randomizes has the same deterrent effect, as an actual stochastic choice, like Schelling suggested. While this means Schelling’s idea can be saved, it is still problematic how we should view contributions of bounded rationality in relation to current deterrence theory. The article suggests that separating the purpose of a model in conjunction with allowing other scientific ideals than model-theory coherence permits a broader and philosophically sounder approach.

The last decade has seen several advances in the study of deterrence. These advances have sparked some strong disagreements regarding interpretation of the models and what their contributions signify. This paper appraises the discussions from a model theoretic perspective. It is argued that when comparing rivalling models three aspects; (i) target, (ii) criteria and (iii) type of purpose should be taken into account in order to make a proper appraisal. Informed by these aspects it is evident that the three deterrence models analysed address different aspects, in different ways and to different ends. From this perspective, the so-called Perfect Deterrence model must be recognised as a clear advancement in the research field. Model comparison will always be context relative and a plurality of models should be viewed favourably.

This article considers whether the Somali pirates were deterred by the naval task forces between the years 2009 and 2013. By disaggregating data and using previously unpublished records regarding the naval operations, two areas of operations are identified as potential periods of deterrence. The article uses a model of asymmetric deterrence to study the outcomes and equilibria of the navy-pirate interaction. It is found that the naval operations eventually did deter the Somali pirates in the Gulf of Aden, but that this objective was not met in the Somali Basin. It is concluded that the operational focus on the Gulf of Aden coupled with the fact that the area is relatively smaller than the Somali Basin enabled the naval credibility, thus effectively denying the pirates access to the sea. Conversely, limited attention by the naval units and the long Somali southern coast with its open waters impeded naval control in the Somali Basin. In connection to these findings some conclusions regarding naval deterrence are discussed.