Putin may be an unsavoury character to us in the west> he is after all a KGB shadowmaster, but what is the wests real problem with him effectively annexing Crimea?
The crimea was only given over to Ukraine as some strange post stalin concession in 1954. It remained ethnically Russian with the major black sea naval base there under the USSR. Now there comes a long a Kiev government which immediately tries to ban Russian as an official language , and any other non standard Ukrainian language.
What would the US or Britain, those two well known poorly sanctioned invaders of other countries have done? Fidels son invades Guantanamo? War. Argies Invade Falkands again, War. Porto Rico goes socialist anti america by a democratic vote, now let us call that an insurgency. Belieze and Gibralter?
The precedent is not quite the same as Putins Sileasian style holidays from diplomacy to save ethnic Russians and raise popularity in the great bear vote. However where was any real credence or precedent in the invasion of Iraq? It was an oil-well-grab whereas Crimea is probably going to be a land grab and the destruction of a potentially troubelsome rival black sea fleet.
My point is the allies have all done worse within the last 140 years and within the last decade the insurgencies to Iraq and Afganistan and the continued tacit support for the racist political right in the Holy Land and all their west bank land grabbing have done little for world peace.
Putin is preempting a possible civil disruption crimea vs Kiev, not a civil war, and in many ways he is justified in going in there given the uncertainty of who and howrule from kiev will pan out. If this had been the USA going into a terratory with high allegance to them and many of their citizens, there would be a big presedential conference with a rough translation of what Putin and his cronies will say over the next few days. Only then it would be right.