Earlier quoted context omitted.
I think I may have misread your earlier response. When you wrote "as a first strike becomes possible", who do you think might be doing the first strike, and against whom? Since this was an article about Russia's hypersonic weapons, I assumed you meant Russia. Upon second reading, and with your response now, I am no longer so certain. I agree that missile defense is an expensive fantasy. My view of Russia's hypersonic…
I ought to have explained that. It isn't just Russia who is developing hypersonic weapons, it is everyone who can, and Russia has just been talking about it for propaganda purposes. It could be China doing first strike against US Pacific Fleet, US striking Russia, India vs Pakistan etc. Hypersonic strike really makes a nonsense of wide area ABM and fixed point ABM. The only response is to shoot first, or counter laun…
As I understand it, "first strike" is meant to be such an overwhelming attack that the response is not an effective deterrent. Here's the definition from Wikipedia:
> In nuclear strategy, a first strike is a preemptive surprise attack employing overwhelming force. First strike capability is a country's ability to defeat another nuclear power by destroying its arsenal to the point where the attacking country can survive the weakened retaliation while the opposing side is left unable to continue war.
That is, "China doing first strike against US Pacific Fleet" isn't a the correct use of 'first strike' as it's typically used because while the US Pacific Fleet may be destroyed, the rest of the US military has enough capability to destroy China.
As for 'Response decision time is minutes', that was also true for US/USSR in BMEWS days, designed for 15 to 25 minutes warning against ICBMs. Less for sub-launched. For the UK it was, infamously, four minutes.
So while I agree that it changes things, the (il-)logic of MAD is no different in a future with hypersonic weapons than it was for nuclear weaponry in the 1960s.
The nuclear torpedo is the right kind of bonkers. It highlights the stupidity of the US missile defense strategy, it's doable, and it builds on the supercavitating torpedo designs Russia already has. And it is a much better second strike weapon than first strike.