'I'm astounded at how many people continue to live in the 3rd fantasy of believing Ukraine could somehow "defeat" Russia while still avoiding WW3'
2. The US lost in Vietnam without using nukes. Even more relevant, the USSR lost in Afghanistan without using them! I believe Pakistan has lost 3 straight wars to its arch-enemy, with no nuclear weapons being used.
If we follow your logic to its conclusion, Russia can annex Poland, Lithuania, Germany, France, and so on, and at every step of the way we'd say 'well we can't defeat Russia or else they'll use nukes'. They'd be able to conquer.... everything this way. This seems bad? Would you like to live in this world?