If a nuclear missile is launched at the United States the President has just 6 minutes to come to terms with that and decide to launch a counter attack or not.
If that counter attack is headed to North Korea, any land based missiles will head over the arctic circle, over Russian airspace where similar shoot/no shoot decisions will have to be made in a similar timeframe.
Yeah I did! I’m hoping my library get the book. Hell I might buy it, read it and donate it after