I think you're underestimating the number of target between just the US and Russia. Each has approximately 1600 warheads deployed. Even with using 3 warheads per target, that means over 500 cities/targets in each country destroyed. Of course neither side would use all their active warheads on the opposing country; they would save some for other nations. Then you have to factor in British and French warheads. Israel, Pakistan, India, China and NK would all join in as well. So perhaps the African continent might be spared, and the majority of South America as well. But full scale nuclear war would eliminate North America, most of Europe, a large portion of Eurasia and the Far East.

And then what is left would have to face the fourth horsemen of the Apocalypse; carrying famine, disease, pestilence.

Oh and conventional warfare would occur as well.

> Of course neither side would use all their active warheads on the opposing country; they would save some for other nations

Nor would all of those warheads will detonate, land on target (some will hit and target the ocean) or launch successfully.

> But full scale nuclear war would eliminate North America,

I doubt it. Maybe you're being hyperbolic here, to whit.

If you eliminate the top 20 US ports, the aircraft carriers and a couple military bases (including Washington DC), you have destroyed modern USA but you do have to wait out the sub launches and miscellaneous hidden missile silos. There's little point to sending nukes to Montana, Kansas, etc. Nothing more (probably a lot less). Show me something that asserts anything more is necessary.

You don't eliminate land and population you dont have to, to win a war. Mad-max wastelands are hyperbolic fantasy that ignore basic human agency, imo. Country X isn't scared of refugees or natives of Louisiana forming an invasion force to retaliate so there's no reason to wipe out the land. Again, misfires happen and nuclear fallout is bad for everyone, but that's not the same thing as "eliminating" NA.

True, perhaps 10% might fail. But I think you're underestimating how many targets there are across the US. Both military bases as well as industrial targets. First strike targets would hit Montana and Kansas as both have Minutemen ICBM silos. Omaha would be wiped out since Offut AFB is next door. Louisiana has shipbuilding that would get nuked, as does Wisconsin. If you learn about SIOP, and accept that the Soviets had similar plans, you'll understand. The USSR didn't intend a nuclear war to "liberate" the USA. It planned to destroy the country, not just its military capabilities.

> First strike targets would hit Montana and Kansas as both have Minutemen ICBM silos

80s Russia is not really a good predictor. I simply disagree with both the reasoning and conclusion which has radically changed with technology and revelations about capability between all nations.

I think this kind of proliferation scenario vastly overestimates how many targets any country will bother to target. Aiming at neighbors makes a lot more sense than attacking countries overseas in full scale nuclear war today.

Target lists might not include Aunt Emma's farm, but probably still would take out any important industrial and rural targets: mines, mills, chemical plants, refineries, pipelines, textiles, machine shops, warehouses, granaries...

Civilization would look very different for sure.

Talking about total supply chain collapse.