Sea changes: The future of nuclear deterrence

In order to deter adversaries, a nuclear-armed power must deploy an invulnerable second-strike force; its leadership must display the willingness to use that force under certain well-defined circumstances; and it must make believers out of the prospective foes it hopes to deter, convincing them that its capability is real, and it has the resolve to use it. But new technology is empowering navies to peer underneath the sea, finding deep-running submarines more effectively than ever before. This calls into question the invulnerability of nuclear-powered ballistic-missile submarines, the most invulnerable retaliatory asset there is. This article explores the dynamics shaping undersea nuclear deterrence in the second nuclear age and ventures some speculation about how submarine combat may unfold in the coming decades.