The political nature of a regime matters, for nuclear deterrence remains more art than science. When US National Security Adviser H R McMaster revealed the North Korean regime to be undeterrable, it infused realpolitik back into US defense architecture.
Entire departments of defense must now reckon with what cannot be quantified, namely the ruthless nature of Kim Jong-un’s regime. As Washington engages Beijing in its envelopment of North Korea, the White House needs to fortify its rhetoric to stop the cycle of provocation from Pyongyang.
To succeed, the White House needs credible threat deterrence and accurate deployment of missiles to engage North Korean launches at the boost phase. Finally, the US needs strong regional allies for the endgame.
If the US takes Pyongyang seriously, it must have a political roadmap to denuclearize the Korean Peninsula without upsetting Beijing’s calculus.
US intelligence agencies had believed that North Korea would not have reliable intercontinental ballistic missiles (ICBMs) until 2022. But last July, Kim successfully tested two missiles capable of reaching the continental United States. In September, he conducted an underground test of a thermonuclear device.
The Americans possess Ground-Based Midcourse Defense (GMD). These missiles are based in Alaska and California and could intercept Pyongyang’s ICBMs. However, the US Missile Defense Agency’s math isn’t good. The actual kill rate for GMD interceptors is 56%. To reach a 97% kill rate, the Americans would need to launch four interceptors for each warhead striking the continent.
America’s best options are regional, local deployment of Patriot missiles and submarine-based Aegis backed by Terminal High Altitude Area Defense (THAAD) based in South Korea. Intercepting Pyongyang’s missiles at the boost phase is feasible, but there are serious strategic questions about the GMD because it depends on hitting a fast-moving target from further away than a locally based deterrent.
The Donald Trump administration’s calculus is to go regional and local. As of this writing, however, South Korean politics makes THAAD unreliable. This leaves the US with Aegis options.
The Americans are harnessing other nuclear deterrents, but they will not be available until 2025. The Multi-Object Kill Vehicle would allow each US interceptor multiple hits at a single incoming warhead. Drones carrying solid-state lasers could accompany an identified warhead for a kill after its vulnerable boost phase. But these and other options are a decade away.
Classical nuclear deterrence remains in play for the White House. To succeed even partially, the US needs credible leadership aimed at Beijing to seek regime change in Pyongyang.
Don’t count Xi Jinping out, for he may deliver a coup de grace on behalf of Chinese interests.