The main reason for US/NATO not to renounce first strike was because it would be fairly easily overwhelmed by Warsaw Pact forces if WP attacked conventionally. Probably some kind of large WP exercise turned real very quickly combined with Spetsnaz causing havoc behind NATO lines.
First strike was needed in order to slow things down and do some damage, in theory to a) give the US time to rush conventional forces to Europe, b) bloody the nose of WP enough to make them think twice and c) destroy as much as possible of the WP rear areas and reinforcements. If the WP had gone through the Fulda Gap or the South option near Switzerland -tactical nuclear mines, Special Operations nuclear devices, tactical nuclear artillery, tactical aircraft attacks etc would have been used pretty quickly on them.
In reality it probably would have escalated to far worse than that pretty quickly I'm guessing.
It remembers me of a fictional documentary like 20 ago in German TV covering the third world war. The premise was a military coup in Russia. Back then, Jelzin just squashed the coup attempt against Gorbatshev. The development was very cold war like, focused on Germany and ended with a full scale nuclear war. Quite chilling. Only criticism I would have is that the Russians were the bad guys, so.
Edit 2: It is set before the fall of the USSR and the German reunification, classic cold war stuff. Just watching it. Forgot the details, but damn the fall of the iron curtan could really have ended differently. Basically, Gorbatshev was forced to step down and military hawks took over.
Only skimmed the timeline quickly of the video quickly (ticker headlines gave a good indication of events) and the script seems to roughly follow modernized equivalent events of the first hour of the movie The Day After from 1983. (a worthy watch but not really for enjoyment) https://www.youtube.com/watch?v=Iyy9n8r16hs
Do yourself a favour and never watch the BBC Movie from the 80s called Threads about a nuclear war breaking out. Incredible movie but by far the most depressing thing I've ever watched. I felt down for days after watching it during college one time. Never been so effected by a movie. Quite a remarkable piece of work.
Another is Countdown to Looking Glass. It starts out as being told through live news reports although I guess the writers couldn't find a way to maintain that type of storytelling through the whole movie.
Although it's not nuclear war, a better example in the same vein is Special Bulletin.
Another story I can't validate, is that most of the EEC (at the time) agreed that if there was any attempt by NATO forces to arm and deploy the bombs held inside the european territory and they hadn't agreed, they'd seize them.
Basically, first-strike was a posture in public. The real question was "who commanded it"
Conversely in the early days of NATO, the US nuclear command and control was aggressively re-engineered when it was realized that a 24 year old private on a European airbase with the keys to the arming mechanisms for the on-site nuclear bombs wasn't actually going to deter a European battlefield commander who believed he needed to use them right now.
Daniel Ellsberg was rather alarmed to find that Eisenhower had secretly delegated nuclear release capability to regional commanders who had then delegated authority to fairly low level commanders. This delegation wasn't removed when Kennedy became president.
Rhodes writes about earlier concern whose finger was on what button, iirc when Macarthur panicked about the Korean war and requested local tactical command.
Which is kind of an oral history of the development of the current command and control systems (includes some great notes on things like "how unlikely the air force thought a mid-air collision of nuclear armed bombers was" - the spoiler is surprisingly more likely then it was thought after the second one happened).
First strike was needed in order to slow things down and do some damage, in theory to a) give the US time to rush conventional forces to Europe, b) bloody the nose of WP enough to make them think twice and c) destroy as much as possible of the WP rear areas and reinforcements. If the WP had gone through the Fulda Gap or the South option near Switzerland -tactical nuclear mines, Special Operations nuclear devices, tactical nuclear artillery, tactical aircraft attacks etc would have been used pretty quickly on them.
In reality it probably would have escalated to far worse than that pretty quickly I'm guessing.