To counterbalance overemphasis of the just cause principle, I am devoting two chapters to the last resort principle. In the first part of this chapter, the idea of last resort is interrelated with the idea of ‘coercive military threat’. In the second part, a ‘penultimate’ (or ‘next-to-last’) resort principle concerning coercive military threats is proposed and supported. Additionally, in the second and third parts, four other resort principles are proposed and supported. In the third part, the idea of last resort is interrelated with the idea of noncombatant immunity. Finally, in the fourth part, the core noncombatant immunity principle is introduced.

I. DETERRENCE AND COMPELLENCE

A. NUCLEAR DETERRENCE

During the Cold War, writings on the subject of ‘nuclear ethics’ were primarily concerned with the ethics of nuclear deterrence. The central question was this: is it morally permissible to deter a nuclear attack by threatening nuclear retaliation? There was also the related question of ‘first use’. Is it morally permissible to deter a conventional attack – in particular, a Soviet invasion of Western Europe – by threatening nuclear retaliation?

The subject of nuclear ethics might presently appear to be outmoded, now that the Cold War has ended. However, it has been revivified by the threat of ‘rogue states’ and terrorist groups armed with nuclear weapons.