Putin saw the Ukrainian revolution as a challenge to him personally, and I think that's why he, in fact, over-reacted. I think his occupation of Crimea and then annexation for him was actually a mistake from Russia's point of view. And then his invasion of Eastern Ukraine was also a mistake. He imagined that he would invade Eastern Ukraine and then eventually split the country in half, and he discovered that in fact, Russian-speaking Ukrainians are not Russians, and they didn't support him.