The ATACMS are the latest in a long line of "red lines" that the US wouldn't cross that, well look at that, they went and crossed (F16s, APCs, Abrams/Leopard tanks, NATO personnel and now the latest missiles, plus a few more I'm probably forgetting).
I just finished that Glen Diesen book and the later chapters on the war, particularly the information war, are a great, relatively short, summary of what a massive lie the whole proxy war is.
I laughed out loud at the observation that Russia was (according to the US) repeatedly bombing the nuclear power station that they were in control of but somehow not bothering to do the same to all the ones still under Ukrainian control. Ditto with the Nordsteam and the "Russia did it" that suddenly changed after SH's story into "Oh rogue Uki group did it". You wonder how people can't see through this garbage. ...no amount of cajolery, and no attempts at ethical or social seduction, can eradicate from my heart a deep burning hatred for the Tory Party...So far as I am concerned they are lower than vermin.