Abstract With the extension of the concept of security that has occurred over the last few decades, formulating security policy is inherently problematic. Even if one takes a narrow state-centric view of security as military security behind a territorial line of defence, threats are already enormously difficult to assess. After all, states do not readily provide information about their military capacity and gauging their intentions is a problem in itself. Moreover, those intentions are not static, but can change over time. States can also mislead one another with regard to their capabilities and intentions. The history of international relations is replete with examples of threats being underestimated, exaggerated or incorrectly interpreted and of political failure to respond to accurate estimates and pinpoint strategic analyses. Furthermore, states also have to estimate how other states will react to their own actions and omissions. History is therefore also filled with examples of unintended consequences.