The US would probably defend Taiwan if the CCP invaded it. I don't think we would ever use nukes.
I've wondered if China encouraged Russia to invade Ukraine to weaken them so they can become a Chinese vassal state to supply raw materials.
War crimes are absolute, there's no "if you weren't first, you get one free".
Anyone expecting nuclear retaliation for the strikes that have been made inside Russian territory has no grasp on what it really means for a country to use a nuke, or has no confidence in a nuclear power understanding the basic game theory of what would come next. Russia would never use a nuke when a small number of missiles or drones made it past their air defence and cause minor damage on Russian soil.
Wiping out significant portions of their army, navy, and air force for a fraction of a single year’s budget and not a single American death?
The Cold War led to the arms build up it did because of exactly this paradox: on close inspection, it seemed unlikely the US would lose the Eastern seaboard cities just to protect Berlin, for example.