I wouldn't call Putin smart - Russia overall is a fairly failed state. They could've been in a much better position. Perhaps maybe smart in terms of satisfying his own ego.
He’s getting what he wants and successfully destabilizing the US, and now has an invite to the White House. Does anyone think this isn’t going to end with Russia gaining Ukrainian territory and getting the sanctions dropped? How is Europe going to behave when they can’t be sure America is going to protect them?
Yes, Russian Empire failed 100+ years ago, but Russian Federation is strong enough to send hundreds of thousands to death to achieve their goals. It far from a «failed state».