I think there is a rational reason Russia/Putin have done it. This video explains a couple possible reasons that I had not considered before:
Dismissing it as the actions of a madman only blinds you to look in the short term.
I never said Putin couldn't rationalize it. Of course he can, it's about security, both territorial and economic.
The thing is, it's still a dangerous power grab, an invasion of a country that had not joined NATO.
Invading Georgia was a dangerous power grab, same with Crimea.
But I think he completely underestimated the task at hand in Ukraine.
I also think, besides the economic and territorial security reasons, Putin has drank his own nationalistic cool-aid. He cant shake the KGB background and is empire building.
I didn't know about Crimea's fresh water supply, that is interesting.
Still doesn't change my view that Putin is a dangerous megalomaniac.
I'm also not sure, given article 5, that NATO nations would ever have admitted Ukraine. The EU maybe, but not NATO.