First-strike weapons destroy your enemy's ability to retaliate. Second-strike weapons preserve your ability to retaliate after a first strike.

Missile defense systems constitute first-strike technology. Suppose you build an effective[1] missile defense system. You could launch a pre-emptive nuclear strike against your enemies. If your enemies are growing stronger relative to you then you are incentivized to launch a nuclear strike against them, before they can build their own missile defense system.

It is impossible to defend a missile silo against a nuclear first strike because the position of a ground-based missile silo is fixed and few things provide adequate armor against a nuclear warhead. Airfields for bombers are even harder to hide. Submarines are relatively difficult to locate and destroy. Submarines are too small to launch a massive, overwhelming first strike. Submarines are second-strike technology.

First-strike weapons promote instability because they incentivize actors to strike first. Second-strike weapons promote stability because they make it safer for actors to wait. The more you can wait the less likely you'll be to gamble everything on a desperate first strike or to retaliate against false alarms.

This doesn't mean we should put all of our doomesday devices on submarines. That's a single point of failure. A diverse arsenal of delivery systems is more robust than relying on a single technology. China's submarines are (for now) less advanced than Russia's and the United States'. If China put its nukes on submarines it is plausible that its enemies could wipe them all out in a pre-emptive strike. This may be related to why China is currently expanding its ground-based nuclear missile capacity.

A world of second-strike technologies tends to incentivize peace. A world of first-strike technologies tends to incentivize pre-emptive strikes.

  1. Perfectly effective missile defense is implausible against a peer adversary (excepting a successful pre-emptive cyberattack), but we can imagine a world where the United States deploys a successful missile defense system against a non-peer adversary against North Korea. ↩︎

New Comment
5 comments, sorted by Click to highlight new comments since:

Those 3 new silo fields are the most visible but I'd guess China is expanding the mobile arm of its land-based DF-41 force (TELs) a similar amount. You just don't see that on satellite images. The infrastructure enabling Launch on Warning is also being implemented which will make those silos much more survivable, though this also of course greatly increases the risk of accidental nuclear war. I'd argue that those silo fields are destabilizing, especially if China decides to deploy the majority of their land-based force that way, because even with a Launch on Warning posture there will be at least some use-it-or-lose-it pressure during a conflict, while the mobile and sea-based deterrent are stabilizing because they for the most part lack that issue. Similarly, hypersonic weapons including the much-discussed recent tests are stabilizing because they shatter US delusions of any protection offered by its BMD system, now and future. There are few practical differences with regular ICBM warheads besides the ability to better penetrate defences: they're in fact slower.

The issue with China's current SSBN (the Type 094) is twofold: more noisy and the SLBM they carry has relatively low range, so they have to venture further into the Pacific to hit much of the US mainland, both of which render it more vulnerable to detection. The upcoming 096 solves this, both being quieter and allowing it to fire from a protected "bastion" in Chinese coastal waters.

I'm willing to bet the Pentagon's projection that China will have 700 warheads by 2027 and 1000 by 2030 will be revised upward again next year, and some in the US military seem to agree with me. In light of this I'd strongly suggest those in the community working on nuclear risks (e.g. Rethink) shift their main focus from the US-Russia scenario to China, especially with how hard everyone in the West is dying to go to war with China these days haha.

This seems very simplistic.  Outside of doomsday weapons (and even for those), the continuum from first-strike-only (cannot be used creatively) to retaliation-only (cannot initiate, but will be devastating in response) is pretty muddy and unclear.  And rarely is the decision to invest in such things exclusive - one generally wants maximum optionality, not a maximization of any one behavior.

I don’t agree that one generally wants maximum optionality. Too much optionality for first strikes makes you a bigger threat, which may worry others to the extent that they first-strike you. If, say, the Jamaican government woke up tomorrow to find itself in posession of nukes and launchers for them, it would be a headache for them, they’d probably wish it never happened, and try to conspicuously give up the weapons, so that other nations didn’t view them as a nuclear threat. Giving up first-strike options can often make you safer, which I don’t think is true for second-strike options.

Missile defense systems constitute first-strike technology.

I think it is dual-use. A strong (compared to the offensive capabilities of a possible adversary) missile defense is a first-strike technology. A weak missile defense can be a very important second-strike technology.

E.g. in the context of US-China: Given the differences in the amount of warheads and delivery systems a strong US missile-defense system could be a destabilizing first-strike technology. On the other hand, a weak Chinese missile-defense could be stabilizing by enhancing the second-strike capabilities of China without harming the second-strike capabilities of the US.

You're not wrong. Context does indeed matter. Few systems fall perfectly into first-strike vs second-strike.