Putin will do as he wishes.
We are powerless to stop him.
Pootey wants Crimea to protect his military port on the Black Sea. So he shall have it. I doubt he will try to take and keep all of the Ukraine as it will have the same outcome as Afghanistan. A war of attrition from a group of people who hate Russia’s guts. He can have the Crimea back with little or no punishment.
He was always going to do this.