You vastly overestimated the dammage from a MIRV. Nukes are sub liner as a higher percentage of the energy ends up in the upper atmosphere as you increase yield. Nagasaki's Was 20kt and had favorable geographic conditions along with wooden buildings and a large number of people from the same city survived. 500kt still have left survivors in the same city though few.
So, yes a MIV could take out 8-10 cities across Texas while not impacting 99% of the land. But, a more likely approach is to carpet bomb suberbs and redundantly target cities with different warheads from different ICBMs.
Thus, 1000 MIRVs would not get 1000x the dammage as single areas would be targeted multiple times and of course targets get harder to pick. Central West Virginia for example due to all those mountains and minimal population would take a lot of nukes or largely get left alone.
> So, yes a MIV could take out 8-10 cities across Texas while not impacting 99% of the land. But, a more likely approach is to carpet bomb suburbs and redundantly target cities with different warheads from different ICBMs.
Why? Wouldn't it be more useful from a militaristic perspective to take out enemy missile silos, industrial plants which could be converted to produce wartime materials, and to take out military bases? Essentially, target cities, ignore the residential areas except for ones that are near a missile silo? What strategic advantage could possibly come from carpet bombing suburbs?
The world only has on the order of a thousand of these things. Russia, as the GP points out, only has ~300. They can't just glass the opposing hemisphere, they have to pick and choose important targets.
Total war, if you reduce the US population from 300 million to 10 million we are a vastly smaller threat mid term. Consider, if you removed everything but 1,000,000 infantry they would need to go make food, bullets, boats etc. On the other hand if you have 100 million civilians they can quickly train a few % how to shoot and will be very angry while producing a surplus to keep a war going.
The general assumption is an ICBMs counter attack happens when your attack is in the air. So, you would mostly be hitting empty silos thus your country has little military or economic strength left. Worse, it's much cheaper to fake some silos in the middle of nowhere than a suburb. 'Wasting' nukes on corn fields is very costly.
How has a 500kt warhead left survivors in a city? No warheads or bombs that large have ever been deployed in an actual conflict and so have never been used on a city.
The 100% kills zone is surrounded by a much larger 99-95% kill zone. Militarily 98% = total destruction, but when you start talking about 100,000 people you need several 9's.
So, yes a MIV could take out 8-10 cities across Texas while not impacting 99% of the land. But, a more likely approach is to carpet bomb suberbs and redundantly target cities with different warheads from different ICBMs.
Thus, 1000 MIRVs would not get 1000x the dammage as single areas would be targeted multiple times and of course targets get harder to pick. Central West Virginia for example due to all those mountains and minimal population would take a lot of nukes or largely get left alone.