Yes, because Putin is a russian imperialist.
Why did Finland drop 75 years of neutrality with Russia and quickly joined NATO?
Because its treaties with Russia were worthless just like all the treaties Russia signed with Ukraine promising to recognize its borders.
No. Putin has more nationalistic aims, not imperialistic ones.
We are the ones with imperialism on our mind.
Putin kept the treaties until 2014, when we told him to pound sand when he broached the subject of Russian security.