Earlier quoted context omitted.
Kahn actually ran studies to come up with his numbers of a nuclear war causing a ten year economic regression and only killing 50% of a country. His point was that on a long enough timeline it would/will eventually happen, and with adequate preparation a country could ensure both objective victory and survival for the majority of its populace and civilization. Someone has to think about the unthinkable. Wishing nukes…
Ellsberg's The Doomsday Machine: Confessions of a Nuclear War Planner is one of the few books that has literally given me nightmares. Imagine reading memos with stuff like "we plan to kill at least 600 million people, probably a lot more, a lot of them our allies" ....
https://apjjf.org/-Daniel-Ellsberg/3222/article.html
The exact quote that stunned me being:
"The total death toll as calculated by the Joint Chiefs, from a U.S. first strike aimed primarily at the Soviet Union and China, would be roughly 600 million dead. A hundred Holocausts.
I remember what I thought when I held the single sheet with the graph on it. I thought, this piece of paper should not exist. It should never have existed. Not in America. Not anywhere, ever. It depicted evil beyond any human project that had ever existed. There should be nothing on Earth, nothing real, that it referred to."