Future nuclear weapon policies James M. Acton

(Some) elements of nuclear posture Force size and structure Deployed and reserve systems; readiness status Military Organization Troops; training; procedures; operations Enabling systems Command and control; early warning; ISR; targeting Infrastructure Warhead production/maintenance facilities; industrial base; test facilities Declaratory policy Statements; training and exercises; domestic discourse War plans Treaty obligations

Questions raised by reductions Can U.S. fulfill “deterrence” requirements? Will weapons reach target? Reliability; pre- and post-launch survivability Will weapons destroy target? Yield, accuracy and target location error Can requirements be revised? How will allies/adversaries view U.S. resolve and capability? What will the effects on “strategic stability” be? …

Current U.S. force structure PlatformMissileWarhead ICBM(Silo based)Minuteman IIIW78; W87 SLBMOhio-class SSBNTrident-D5W76-0/1; W88 Heavy BombersB-2(Gravity bombs)B61-7/11; B83-1 B-52HALCMW80-1 (+ gravity bombs) “Tactical” fightersF-15E; F-16C/D(Gravity bombs)B61-3/4/10

Future of the triad Political context crucial; in practice force structure will be determined by politics of the moment as much as nuclear strategy ICBM replacement will probably be delayed further (beyond 2020); early abandonment very unlikely (jobs!) Very strong support for SLBMs Multiple decision points related to heavy bombers and tactical fighters coming up Air leg most vulnerable

Arguments for heavy bombers and tactical fighters Unique ability to hold buried targets at risk But, how much do these targets really matter? Stealth as alternative to speed for defense penetration But, how likely is effective BMD? Recallable But, how many war plan options include only aircraft? Forward deployment as tool for assurance But, are there alternatives? Signaling as tool for crisis management

A growing role for conventional weapons in strategic war plans? DoD is directed to conduct deliberate planning for non-nuclear strike options to assess what objectives and effects could be achieved through integrated non-nuclear strike options, and to propose possible means to make these objectives and effects achievable. Although they are not a substitute for nuclear weapons, planning for non-nuclear strike options is a central part of reducing the role of nuclear weapons. Report on Nuclear Employment Strategy of the United States (2013) Probably not about large-scale replacement.

Types of target in a “counterforce” attack against North Korea Fixed, soft targets ICBM sitting on a launch pad Fixed, buried targets Warhead storage facilities; leadership; command and control Probably tens, potentially hundreds of metres deep Mobile, soft targets Road-mobile missiles

Massive ordnance penetrator Total mass: 13,600 kg HE mass: 2,400 kg Can reportedly penetrate to 20 m in reinforced concrete (much less than nuclear weapons)

Physics of conventional penetrators From Nelson (2002)

CPGS technological approaches

Comparison of penetrator effectiveness MOPCPGS V (m/s)500 [?]1,000-1,200 m/A (kg/m)27,00014,000-21,000

Mobile missile hunting Need to locate and track missiles If using standoff weapons need to provide inflight target updates (or risk waiting until they’re stationary) North Korea has hundreds of mobile ballistic missiles Only a small fraction might contain a nuclear warhead, but very hard to tell which is which 1991 Gulf War: 1,460 sorties; 0 confirmed kills 2006 Israel-Hizbollah war: 80-90% of Hizbollah’s medium- and long- range rocket launchers destroyed. But, took time and relied on attacking launchers after missiles has fired.

Nuclear v. conventional options Lethal radius from flechette weapon: <100 m, possibly much less (my calculation) TEL can traverse this distance in 10 s Lethal radius from 100 kT nuclear weapon: 2,900 m (McKinzie et al. 2001) TEL can traverse this distance in 260 s Hunting mobile missiles with conventional weapons much harder than nuclear weapons