How would the US fight a Nuclear War?

A comment on YouTube:

“I served 6 years, USN as an MT (Missile Technician, C3 Poseidon missile system) aboard boomers in the mid 80’s. We were responsible for every system (from flight control equipment, hydraulics, heating/cooling systems, every aspect from loading to close out) and I remember every time we drilled for launch how much weight everyone carried knowing what it meant if it were an actual launch.

Knowing exactly what would come after, and knowing what the world would be like if we were to actually make it home. We all knew from extensive training exactly what these weapons would do, exactly how it performed when deployed from launch to detonation and the result, and I promise you it’s scarier than what you could possibly imagine.

I also know that it’s a necessary weapon and I pray deterrence will still be enough to prevent an attack on US soil. You cannot put this genie back in the bottle. Contrary to movies and what most believe, there is no detonation button to blow it up in space. When it launches it will reach its targets with precision, and it will destroy everything in it path and would only take our sailors minutes to launch every one of them. Let’s pray we never have to. There’s no do overs.”