Time

Is time on Ukraine or Russia's side? 

Some argue any ceasefire or other actions to freeze the conflict benefits Russia because they can simply regroup and invade later.

On the other hand, Russia keeps descending into a lower geopolitical situation year after year vis-a-vis China and the US. Whereas Poland and other Eastern European countries are now hip to the game and will plan accordingly. Not obvious to me Russia will be in a better position in say, 10 years. Also, Putin might die. 

Then again, Ukraine might depopulate. Would you want to live next to a nuclear armed neighbor with designs on your land? Perhaps not. But if you want a free country, you are going to need to be willing to fight and fight for it. Not like the US was created overnight. We had to fight the War of 1812...