This Policy Analysis explores the broad issue of nuclear weapons and their role in the international security environment. It is a complicated issue, and has been for over sixty years. Within the space of a month in the second half of 1945, the United States successfully tested the world’s first nuclear weapon (on 16 July) and subsequently dropped two nuclear weapons on Hiroshima and Nagasaki (6 and 9 August respectively) to bring to an end the Second World War. That chain of events, Colin Gray once observed, told the whole world the only secret worth knowing in the nuclear age: that nuclear weapons can be built and they do work.
The events also outlined in stark form the central puzzle of nuclear strategy: how can such destructive weapons make a positive contribution to international security? Don’t such weapons make a nonsense of the supposed relationship between means and ends in warfare? This central puzzle was complicated by a secondary puzzle: the puzzle of proliferation. How could nuclear weapons make a positive contribution to international security if the weapons themselves were to spread into many hands?