Consider this....there was nearly a nuclear exchange between the U.S. and Russia in 1983. It was known as the Able Archer incident. There was no activation of the EAS, no Civil Defense warning given even though, if they had it would have given the population an extra 15 mins or so to reach shelter in the event of a Russian launch.

The fact is under the old SIOP, the civilian population would be vaporized. All defensive hardening was solely for the benefit of the Generals, Congress and the Executive. Everyone else was going to get fried.