This article investigates the technical rationalities of modern forms of government. Conceived in a Foucauldian vein, the paper argues for an interpretation of security dispositifs which sustain the structures of modern government. The main argument developed in the article is that there is a difference between two securities diagrams: the preventive and the anticipatory. The first one is using rational devices like the actuarial table while the second is aiming to instrumentalise the imagination.