You have 2 first strike options.
1) that will target your opponents nuclear capabilities (ensuring that no 2nd strike is possible)
2) that will target everything including population centers to achieve maximum destruction.<p>In both of these scenarios if you are attacked first (early warning) your only option is to attack their centers of population to either prevent an all out invasion or to retaliate.<p>This is exactly why MAD sort of works, because it actually ensures mutual destruction of not only the nuclear and military capabilities but also of all national and human infrastructure as the only possible answer to even a limited nuclear first strike is &quot;fire zee missiles!&quot;.
Or to put it in a more structured manner there is virtually no room for proportionate response when it comes to a nuclear attack. When there was it was the biggest threat to &quot;MAD&quot; since it more or less would ensure that any side that gains sufficient advantage would be prone to launching a first strike.
Because of this very fact the nuclear arms treaties between the USA and then the USSR limited fixed launch site while promoting mobile launcher and nuclear missile subs as much as possible as the guaranteed 2nd strike capability of both nations was what MAD was actually built upon.<p>But MAD is not without it&#x27;s faults, heck so far i think Norway out all countries was the one that brought us closest to total nuclear war.
<a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Norwegian_rocket_incident" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Norwegian_rocket_incident</a>