Hypersonic weapons and the future of nuclear deterrence

It is widely accepted today that hypersonic weapons pose insurmountable challenges to nuclear deterrence. Although speed has always been a critical factor in warfare, the development of hypersonics provides unprecedented advantages in terms of the speed and agility of missiles. The increase in the speed and agility of hypersonic missiles drastically reduces the response time of nuclear states, encouraging the pre-emptive use of force. Two arguments inform the latter claim. The first holds that the speed and agility of hypersonic missiles are likely to render existing and future missile defences obsolete. The second contends that the failure of missile defences coupled with the reduction of the response time of nuclear states encourages the pre-emptive use of force. Where nuclear states are unable to field survivable second-strike forces, the stability of nuclear deterrence becomes highly problematic. Besides these arguments, the dual-use nature of hypersonic weapons ostensibly increases the risk of nuclear escalation. Against this bleak assessment, in this article, the author questions the destabilising effects of hypersonic weapons on deterrence stability, arguing that nuclear deterrence is – and is likely to remain – deeply stable. A thoroughgoing consideration of the strategic implications of nuclear weapons provides optimism about the stability of nuclear deterrence in the face of the development of hypersonic weapons. Two arguments are advanced in support of the continuing stability of nuclear deterrence. First, missile defences have (and are likely to remain) inefficacious, with the development of hypersonic weapons merely reinforcing (rather than establishing) this fact. Second, a would-be aggressor contemplating the pre-emptive use of force would have to believe that it could destroy all of an adversary's nuclear force before any can be launched. (author)