Once again the Western powers are becoming, bit by bit, embroiled in other countries affairs that has little to do with them. This is a Russian problem involving the old states of the USSR.
In this instance though, leave the Ukraine problem alone as it is a whole mix involving Russians, Russian speaking Ukrainians who want to be with Russia, plus Ukrainians who want democracy but are as bad as the rest when considering what others want!
By this reckoning Lizzie, if it's OK for Russia to interfere because Ukraine is a former USSR state, then it would have been fine for Britain to go and kick some butt in Zimbabwe, to protect the English speaking ethnic Brits living there. Had we done that Britain would have been roundly condemned by the international community and rightly so.
Russia should stay out of Ukraine as well as the West and let the Ukrainians sort out their own problems. I'm sure that the ethnic Russians in Ukraine are free to move to Russia if they want to live under Comrade Putin! 
Firstly and I cannot emphasize this more strongly, Ukrainians are not Russians any more than the Irish are English. Yes, the Irish are Celts like the Welsh and Scots, likewise Russians, Ukrainians are Slavs, but like the Irish and English they have different cultures. They also like the Irish with Eire, their own nation, which they want to keep. If we decided to send a 5th column and irregular troops into Eire to put it back under British subjugation we would be, quite rightly, condemned internationally and could expect sanctions or worse. The Irish are proud of their nation, their independence and their right to self-determination and likewise so are the Ukrainians. This is why the Ukrainian anti-western presidential candidates in the May election only got 8% of the vote between them. All regions voted with a majority for the current President where they are united against a common enemy Russia. The Russian terrorists in East Ukraine have been bitterly complaining they have received virtually no support from the local population who don't want them there and that includes the ethnic Russians, who also like the freedoms, denied in Russia like a free press, freedom of expression, the right to demonstrate, belong to free trade unions etc., etc.
Putin, like Stalin and Hitler is out to build an empire. Their economy is tanking and thats make him and his ambition to be president for life vulnerable. What he is doing is about Putin and his survival as a dictator, along with his 'yes man' inner circle, not anything else and this is what makes the situation in Eastern Europe so dangerous. If he gets away with this, Moldova and Belarus will be next, followed by the Baltic states, then the rest of Eastern Europe, unless NATO and the US intervene to stop him and I think we all know what that will mean.

Hitler was encouraged by appeasement and indifference and likewise Putin is relying on the same with his "Asymmetric Warfare and Plausible Deniability". This is a new form of 21st century warfare or the revival of an old one used in the 19th century?
Whether we like it or not we are all part of planet earth and pawns in the major powers "Great Game" (which was coined by the British as part of the British-Russian wars and vying for influence in Asia in the 19th century) that has been going on hundreds of years. Unfortunately, when a major power decides to rewrite, what the rest thought were agreed rules of conduct, treaties and International Law, using military might, it is very easy for many countries to get drawn in to protect their interests, which we have seen with WWI and WWII.