Hmmm....nobody talks about the US military taking charge. Their oath to the Constitution and a duty to refuse illegal orders weigh heavily here. Russia is being bled dry in Ukraine, they don't have the troops or armaments and certainly not the logistics to attack NATO. If Putin wants to win such a contest he'll need to go nuclear early in the contest because he is simply outclassed by the US. The US would of course have to respond in kind. Worth knowing: Russia has a population of just over 142 million shrinking at 2 percent per year and they do not have the productive capacity to keep their troops in the field supplied. Right now they are short 5 million workers. Russia's GDP is about $1.7 trillion, that of California alone is something like $2.6 trillion. Russia cannot fund such a war. The only way for Putin to win is if he can install Trump. Trump is declining to say the least. So, this amounts to a nice scenario for a novel but that's about it.