The world is a violent place, but one country very rarely annexes the territory of another. The formal and forcible incorporation of Crimea into Russia marks the first such act in Europe since 1945. Mercifully few people have been killed, but Vladimir Putin’s intervention in Ukraine has struck at the central principle of post- war order, namely that no state will enlarge itself at the expense of another. In the process, the equilibrium of Europe has been deranged.Against this background, I propose to re-examine the case for unilateral nuclear disarmament. I must first declare myself: I believe that Britain should maintain its nuclear deterrent. But my interest here is not so much to rebut unilateralism, as to analyse the argument and see where its logic leads. As I understand it, th