Thank you, Chris, for your comment about Ukraine's geography. Also, you are quite right that Russia today is weaker than the USSR, and the West stands fully behind Ukraine. Another difference is that there was a pro-USSR state in Afghanistan, and the mujahideen were rebels in Ukraine; however, the state and the military are against the invading army.

Russia has a small window for success; if it does not achieve what it is looking for this year, it will have less and lesser chance as the war prolongs. History of invasions shows that the invading army will be increasingly exhausted as the war drags on.