The sea mine is important because it is used. One and one half million sea mines have been used during this century by a wide range of users for a multitude of political-military purposes. The sea mine is used because it is inherently flexible and can give a first, and least escalatory, option in situations requiring a precisely measured graduated response. Minefields can be used to control the actions of an adversary by adjustment of their areas, intensities, timings, targets and durations of effect. This monograph presents an imaginative plan for the use of the sea mine in Australia's defence. It explores uses of the sea mine as a peacekeeper, capable of eliminating escalatory 'eyeball-to-eyeball' confrontation between forces. A role for the sea mine as a 'robot policeman' of Australia's EEZ is also considered, together with the sea mine's traditional role as a proxy warfighter, one which issues no communiques and never surrenders.