Thread by @james_acton32

Welcome to day two of #nukecon! We’re going to discuss the deterrence and escalation implications of new delivery system technologies with @LauraEGrego, Greg Weaver, Sun Xiangli, and @ElenaChernenko.

.@LauraEGrego: New technologies won’t undermine U.S.-Chinese or U.S.-Russian mutual vulnerability, but could lead to escalation in crises because, for example, of the difficulty of distinguishing a space launch from a FOBs launch. #nukecon

Weaver: Maneuverability of hypersonic systems complicates assessing which targets are under attack.

FOBs/MOBs are more concerning. Potentially extremely short warning times; could undermine ICBM/leadership survivability. #nukecon

Weaver: US/Ru/Ch should stop flight testing FOBs/MOBs and agree not to deploy (if verifiable).

Nuclear-powered cruise missiles could loiter, conduct short warning attacks (even if launched from homeland), and vulnerable to third party catalytic escalation. #nukecon

Sun: New technologies well suited to evading ballistic missile defenses. Not suitable as first strike weapons (accuracy and reliability question times) and short warning times are already a problem given depressed trajectory SLBM launches. #nukecon

Note: FOBS=fractional orbital bombardment system; MOBS=multiple OBS.

.@LauraEGrego: Codes of conduct and norms of behavior are a good place to start in space arms control.

Weaver: Given risks of FOBS/MOBS, it’s irresponsible and dangerous of China not to discuss those risks. #nukecon

Weaver: Mutual assured destruction isn’t a strategy, it’s a condition. The threat that leaves something to chance—the possibility of all out escalation—enhances deterrence through denial of benefits. #nukecon

Sun: It’s speculation that China is developing FOBS.

[Addressing Weaver]So, what is US nuclear strategy then? Is it nuclear war-fighting? #nukecon

Weaver [responding to Sun]: Unlike China, U.S. has published unclassified employment strategy and U.S. officials want to discuss it with Chinese counterparts. U.S. policy focuses on imposition of costs and denial of benefits, as it always has. #nukecon

Jiang (discussant): FOBS is risky (though no clear evidence that China is developing). U.S.-China dialogue is needed. Ban on debris producing ASAT tests is also a good idea and could lead to legally binding agreement. #nukecon

Weaver: Cyber threats to early warning would be concerning but those systems can be effectively defended. AI of more concern if it allows tracking of mobile delivery systems. #nukecon

Sun: Arms control requires all relevant technologies, including BMD, to be taken into account. #nukecon

Weaver: Yes, new technologies are effective at defeating missile defenses but the U.S. has made clear that defenses are not designed to undermine R&C nuclear deterrents and R&C are doing much more than is needed to ensure force survivability. #nukecon