"140 million versus 40 million, but then Vietnam successfully fought off America despite being outnumbered 3 to one, same Afghanistan v russia. when is the last time one country has conquered and annexed another country with an adequate defence force on a permanent basis?"
False analogy. Ukrainians are fighting a much more powerful nation next door to them as distinct from America fighting a war afar, such as in Vietnam and Afghanistan. Having said that, America could have ended both wars the same way they ended the war with Japan, but it didn't. Russia might though as now they have much smaller tactical nukes that would be so much easier and handy to bomb the hell out of Ukranians inside of Russia without too much fallout in the surrounding regions. Nothing to stop Russia from using them inside of Ukraine if things did get carried away and the Ukranians penetrated further into Russia and/or started hitting Moscow with missiles and drones killing civilians. Drones have already been sent to Moscow but so far all of them have been destroyed by Russian defence forces.
