Dealing WIth Putin

I really didn't think Russia would invade Ukraine, i fully expected it to hang around the border menacingly so i was very surprised when i awoke to hear that the Russian military was stomping it's way towards Kiev.
The question now is what can the World do about Putin and his designs on Ukraine?
Military action against a nuclear Russia is out of the question and has been ruled out so it is financial sanctions but he has been building a multi-billion nest egg since taking Crimea in 2014 and it will be the Russian people who suffer, not him.
He has played the same card as America and Britain in their woeful wars against Iraq and Afghanistan of i'm going to invade so just you try and stop me, and now he has and we stand around bleating how awful it all is but unable to do very little to stop him slaughtering whoever gets in the way.
As this plays out on our TV screens, i am conflicted between how to approach it and recent history is not much use.
If we arm the Ukrainians it will just prolong an awful and bloody war and we end up with another Afghanistan and if we do nothing we potentially save hundreds of thousands of lives but Putin would have literally got away with murder and could be emboldened to turn his sights to other nations outside of NATO.      
That only leaves sanctions and they can take up to a decade to work and sanctions don't really do anything to punish the people starting the wars, they are insulated against economic downturns and it is their citizens who have to endure the hardship.
The threat of Human Right Courts won't scare him, George W Bush, Tony Blair and a host of Israeli leaders should have been in the dock but never got dragged to The Hague to answer for their war crimes so hardly likely Putin will, that just for the little guys.
So i don't know the answer when it is one of the most powerful, nuclear armed nations that brazenly invade another nation to remove a leader they don't like but i hope someone somewhere has an answer to it.