[It is what it is because Russia has nukes. ]
If Putin starts anything in that regard, he is gonna lose 140m of his closest friends, and he knows it. That’s why he laughed derisively at the end of Dr. Strangelove’s stupid ending, while watching it with Oliver Stone. Nobody makes decisions in the way Kubrick’s moronic caricatures do.
Putin wants to become Vladimir the Greater, not turn an exterminated Russia into China’s biggest province. He can come back from losing in Ukraine. He can’t come back from an annihilated Russia.
Everything you say is true. But everyone knows the US will not use nukes first. Everyone. Enough of the world believes Russia just might to give it a tremendous advantage.