Crimea leaving Ukraine is a good move towards world stability, in my opinion. It just means that the pro-Russians inside Ukraine will have a peninsular to migrate to. And once the ties have been severed, Ukraine should immediately step up border patrols and tighten immigration from Crimea to prevent Putin from slipping his supporters into Ukraine. So there'll only be an outflow of Russian influence from Ukraine to Crimea, weakening Russia's claims to the rest of Ukraine, freeing Ukraine from further Russian influence. I'm sure the western blocs will be agreeable to this too since they'll get to keep the rest of Ukraine without further conflict by giving Crimea to Russia.
