And before, to the founding of the Russian identity, when confronted with the Khans and the europeans, they (the princes of Kiev) fought for generations, seasonal wars of attrition. And now they are fighting europe, pointing to the dinipter saying "remember?" Plus this war is much more, as it is the first high tech war, and many outside partys are involved in every way. Just think how SK is shitting square ones knowing that NK has troops fighting on the front lines, and is totaly involved in planning, tacticts and strategy.

They have not much choice than to keep at it. Target is control of whole Ukraine as vassal state, anything less is a defeat. They have already spent over 1 million casualties on frontlines. Claiming anything less than whole Ukraine for such price would be a political suicide.