Hypersonic weapons and the future of nuclear deterrence

Abstract

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.