Why aren’t you saying that Russia is playing roulette by attacking NATO adjacent country? Why is it the US responsibility to de-escalate and withdraw support? K

Why aren’t you saying that Russia is playing roulette by attacking NATO adjacent country? Why is it the US responsibility to de-escalate and withdraw support? Keeping in mind that Ukraine would keep fighting and Russia would have hard time capturing and keeping whole country. One part of nuclear deterrence is standing up to bullies and making clear the lines. This includes escalation points leaving flexibility for conventional warfare. Remember that US and Russian pilots fought over Korea and Vietname, and that there are multiple cases of supplying other side. The US has done good job of not escalating because supplying Ukraine has worked well. Russia knows that using nuclear weapons or attacking NATO bases will provoke response, probably aerial attacks inside Ukraine. It is unlikely to escalate beyond that and Ukraine doesn’t need ground help. Attacking inside Russia is too risky. Russia or NATO will never be invaded.