Why I say confirmed our launch is there have been at least one close call on each side. One I remember the details of one was the USSR Officer in charge, Stanislav Petrov, over-rode the information from the radar and 40 years ago, on 26 September 1983, he saved from potential nuclear disaster.
When discussing this with some peers the consensus was that the would have to sound the alarm. Especially now, since it is unlikely a first strike would take out all cities [count on Russian duds], so the survivors would blame the bunker buddies (the higher people, ala Dr Strangelove)
Let’s say two thousand nukes were incoming that would glass this entire half of the world.
At that point… why even fucking bother? We’re talking about optimistically thirty minutes of warning but probably at most half that once we’ve confirmed attack and then we’d ask the president (let’s say two minutes) and have two choices: do we inform the public and do we counter attack.
The response to the first question is going to depend on how religious the president is - do they think people would want to pray before dying? Otherwise, why stress people out when there’s literally nothing you can do. Everyone is about to die, ignorant bliss is probably the best way to spend your last moments.
The second question is more interesting. A country has erased you from the map, do you erase them? Logically, no, what’s done is done and you’ll just be increasing the chances that no humans survive the next centuries of apocalyptic conditions. Let them live on and forgive their aggression… of course you should never say that’ll be your response, if someone asks say “We’ll turn the planet into molten glass. Fuck everyone”… but when push comes to shove a rational person wouldn’t counterstrike.