4 ms·

The worst case is that one country becomes convinced that it can launch a first strike, and then intercept all the retaliatory strikes.

throwaway894345 6y ago
I guess it would be bad if the interceptors were highly concentrated in a single nation or coalition, but as long as each coalition has plenty (relative to the number of warheads) it shouldn't be a problem. Note that the distribution doesn't even need to be very even--let's say each nation is capped at 100 warheads and Russia has 1000 interceptors and the US has 10000--the US doesn't have much leverage on Russia despite an order of magnitude more interceptors. So as long as all of the interceptors aren't concentrated on one side of an engagement (and it would be very unlikely for this to be the case for any enduring period of time) all is well. And of course, there's the additional deterrent of a globalized economy. Most nuclear countries depend on the global economy and have a strong incentive not to devastate it by way of nuclear warfare. The odds of an isolationist country like NK owning all of the interceptors is pretty low IMO.
- ethbr0 6y ago
  Possession of num_interceptors > num_counterparty_ICBMs leads to a few undesirable behaviors. - Increased counterparty desire to build more ICBMs - Increased belief in a successful first strike / acceptable response casualties Both of these make the world a more dangerous place. Better to agree on what we're targeting (smaller nuclear states), and preserve the status quo.
  - throwaway894345 6y ago
    > Increased counterparty desire to build more ICBMs I'm assuming a cap on ICBMs. If nations aren't going to obey these caps then why should they obey a cap on interceptors? > Increased belief in a successful first strike / acceptable response casualties It doesn't follow that (num_interceptors > num_counterparty_ICBMs) will lead to a successful first strike (notably it doesn't follow that the counterparty doesn't have interceptors of their own).
    - ethbr0 6y ago
      Arms control treaties are negotiated in the current context, in country's best interests. Even a desire to build more ICBMs is harmful, as it makes a country less likely to voluntarily agree to ICBM limits in the future. But absolutely agree that ICBM and missile defense are intertwined, so only make sense to negotiate strategic arms control covering both. I would say that it does follow that "sufficient" interceptors, relative to a counterparty's ICBMs, leads to a "successful" first strike. Where "success" in this calculus means acceptable losses. The lynchpin of MAD is that no one is insane enough to argue that the incineration of a major city is acceptable for a first strike. Without ballistic missile defense, that destruction is effectively guaranteed, as long as the counterparty has available ICBMs and is able to launch them. With ballistic missile defense, there's a chance that destruction could be averted. And that chance drastically balloons the risk of a first strike being launched. To put it another way: you're the president, and you're at a meeting of the Joint Chiefs. Open conflict with Russia has broken out in Eastern Europe. Massive amounts of Russian reinforcements are transporting towards NATO lines. No BMD: if we escalate to nuclear, and the Russians retaliate (as stated by their nuclear posture), American cities have a 100% chance of being vaporized. BMD: ... American cities have a 75% chance of being vaporized. That's a terrifyingly different decision, because it opens the possibility that someone decides to take a risk. Because there's a chance things will work out favorably.
      - throwaway894345 6y ago
        I guess I'm arguing that there is a dynamic you're not considering with respect to whether or not to initiate a nuclear strike. I agree with you that an aggressor is more likely to initiate a strike if they believe they have a very high chance of a successful strike (where "success" is defined as destroying the target) and a very low chance of retaliation. However, the scenario we're debating is one in which Russia has its own interceptors so the risk of a successful first strike (US striking Russia) is about the same as the likelihood Russia succeeds in retaliating. If both nations have lots and lots of interceptors relative to the ICMB cap (assuming for the moment that both countries adhere to the ICMB cap), then the odds of any country initiating a successful strike (first or second) becomes relatively and equally low. At that point, it's more effective to pursue conventional (i.e. non-nuclear) warfare, and even if a country does initiate a desperate nuclear strike, it's less concerning because the odds of a catastrophic loss of life are significantly reduced. Would you argue that we would be better off if we fought conventional wars without body armor of any kind? Or would you argue that this is somehow different than the interceptor question? If so, how is it different (degree vs kind and why)? (By the way, I don't see a US president--barring perhaps the current one who doesn't seem concerned with his own best interest much less that of his country--accepting a 75% chance of the destruction of US cities in order to stop a Russian advance)

throwaway894345 6y ago

I guess it would be bad if the interceptors were highly concentrated in a single nation or coalition, but as long as each coalition has plenty (relative to the number of warheads) it shouldn't be a problem. Note that the distribution doesn't even need to be very even--let's say each nation is capped at 100 warheads and Russia has 1000 interceptors and the US has 10000--the US doesn't have much leverage on Russia despite an order of magnitude more interceptors. So as long as all of the interceptors aren't concentrated on one side of an engagement (and it would be very unlikely for this to be the case for any enduring period of time) all is well. And of course, there's the additional deterrent of a globalized economy. Most nuclear countries depend on the global economy and have a strong incentive not to devastate it by way of nuclear warfare. The odds of an isolationist country like NK owning all of the interceptors is pretty low IMO.

ethbr0 6y ago
Possession of num_interceptors > num_counterparty_ICBMs leads to a few undesirable behaviors. - Increased counterparty desire to build more ICBMs - Increased belief in a successful first strike / acceptable response casualties Both of these make the world a more dangerous place. Better to agree on what we're targeting (smaller nuclear states), and preserve the status quo.
- throwaway894345 6y ago
  > Increased counterparty desire to build more ICBMs I'm assuming a cap on ICBMs. If nations aren't going to obey these caps then why should they obey a cap on interceptors? > Increased belief in a successful first strike / acceptable response casualties It doesn't follow that (num_interceptors > num_counterparty_ICBMs) will lead to a successful first strike (notably it doesn't follow that the counterparty doesn't have interceptors of their own).
  - ethbr0 6y ago
    Arms control treaties are negotiated in the current context, in country's best interests. Even a desire to build more ICBMs is harmful, as it makes a country less likely to voluntarily agree to ICBM limits in the future. But absolutely agree that ICBM and missile defense are intertwined, so only make sense to negotiate strategic arms control covering both. I would say that it does follow that "sufficient" interceptors, relative to a counterparty's ICBMs, leads to a "successful" first strike. Where "success" in this calculus means acceptable losses. The lynchpin of MAD is that no one is insane enough to argue that the incineration of a major city is acceptable for a first strike. Without ballistic missile defense, that destruction is effectively guaranteed, as long as the counterparty has available ICBMs and is able to launch them. With ballistic missile defense, there's a chance that destruction could be averted. And that chance drastically balloons the risk of a first strike being launched. To put it another way: you're the president, and you're at a meeting of the Joint Chiefs. Open conflict with Russia has broken out in Eastern Europe. Massive amounts of Russian reinforcements are transporting towards NATO lines. No BMD: if we escalate to nuclear, and the Russians retaliate (as stated by their nuclear posture), American cities have a 100% chance of being vaporized. BMD: ... American cities have a 75% chance of being vaporized. That's a terrifyingly different decision, because it opens the possibility that someone decides to take a risk. Because there's a chance things will work out favorably.
    - throwaway894345 6y ago
      I guess I'm arguing that there is a dynamic you're not considering with respect to whether or not to initiate a nuclear strike. I agree with you that an aggressor is more likely to initiate a strike if they believe they have a very high chance of a successful strike (where "success" is defined as destroying the target) and a very low chance of retaliation. However, the scenario we're debating is one in which Russia has its own interceptors so the risk of a successful first strike (US striking Russia) is about the same as the likelihood Russia succeeds in retaliating. If both nations have lots and lots of interceptors relative to the ICMB cap (assuming for the moment that both countries adhere to the ICMB cap), then the odds of any country initiating a successful strike (first or second) becomes relatively and equally low. At that point, it's more effective to pursue conventional (i.e. non-nuclear) warfare, and even if a country does initiate a desperate nuclear strike, it's less concerning because the odds of a catastrophic loss of life are significantly reduced. Would you argue that we would be better off if we fought conventional wars without body armor of any kind? Or would you argue that this is somehow different than the interceptor question? If so, how is it different (degree vs kind and why)? (By the way, I don't see a US president--barring perhaps the current one who doesn't seem concerned with his own best interest much less that of his country--accepting a 75% chance of the destruction of US cities in order to stop a Russian advance)