More importantly, MIRVs make ICBMs unstoppable in practice. To defend against a single ICBM past the separation stage, you'd have to waste one interceptor per reentry vehicle. An ICBM can easily take 6 or 10 warheads. The attacker could further frustrate your defenses by making 2/3 of the RVs fake and sending two more ICBMs, at little extra cost to them - and now you have to use 3x as much interceptors to stop such attack.
Which is an important to aspect to MAD. While nuclear countries are adversarial, detterent-deters like laser AA and hypersonic cruise missiles are destabilizing.
Yeah. MAD requires for all participants to believe none of them can launch an attack on another that would kill the enemy's capability to retaliate before said retaliation. Too fast weapons destabilize MAD, and so do too good defensive technologies (or even credible rumors about them).
good defensive technologies are not destabilising when one credibly has no first strike capability. (this is, of course, only an option for third world countries)
If you have no first strike capability, you're not participating in MAD. With hypothetical superior defensive technologies you wouldn't be bossed around by folks with nukes, but you couldn't threaten them either. I'm saying hypothetical, because they don't exist yet - the primary defensive technology against superpowers is the ability to execute a retaliatory strike, i.e. to participate in MAD. And defensive tech cannot be allowed to progress faster than offensive tech, lest it breaks MAD and plunges the world into nuclear war.
Even sudden emergence of such superior shield in a random country with no offensive capabilities would be pretty destabilizing. The mere existence of it would put everyone on high alert, as all the nuclear powers scramble to replicate it before others do. And if said country where this technology emerged would even suggest they may be considering extending protection to one nuclear power and not the others, that alone would be enough to force others into striking first.
I don't know how superior (or even effective) it may be, but the existence is (and has been) well known: lots of underground concrete sufficient for the entire population (Saint Barbara has a strong local cult).
Nuclear powers (especially those who have already made first strikes) can't do this because (a) they would have to somehow retroactively do all the construction which we spent the whole cold war doing (it's much easier to put a shelter in before you build the rest of the building than after), and (b) as you point out, it would destabilise MAD.
(having no natural resources worth bombing us for is probably more effective. We don't want to threaten anyone, we would just prefer to make decisions, such as those concerning our bill denominations and our central bank strategy, by ourselves)
Tinfoil conspiracy theory: MAD explains why the US doesn't have decent subways :-) How deep are Warsaw's?
Not tinfoil: during the US/USSR cold war, it was the west- and east-germans who were most likely to get tactically nuked. In a hypothetical Oceania/Eurasia world, I'm guessing that distinction has moved to PL and BY. Luckily for you, the current two-minutes hate is directed to Eastasia.
On the brighter side: what do you think of Kongres Futurologiczny?
