If the events in Ukraine were happening in Mexico or Canada then the US would quite legitimately be worried and entitled to take action to protect her interests but Russia is not so entitled!
I'm not sure that if the situation was changed and it was either Mexico or Canada who had seen massive protests against the government that we'd see the US annexing Newfoundland or Baja California (two pick two bits of those countries) and claiming them as US territories.
I could see them deploying troops to 'keep the peace' but to rock up and say 'this is ours now' I don't think so.
And really? Fighting for survival? Give me a break...
Maybe not from outside (though I wouldn't be surprised if China didn't occasionally cast an eye at all those resources sitting in Siberia where there are very few Russians) but the demographic and economic picture most certainly isn't pretty in the long term.
Then again there is an old saying about Russia that she is 'never as strong as she looks nor is she as weak as she looks'.
I'm more interested in the MILLIONS who have been killed since 2001 and in Entire Countries turned into HELLHOLES by the USA elite's continuing struggles to maintain World hegenomy.
Afghanistan would meet most of the criteria of a 'hellhole' prior to the Coalition invasion and occupation and since the March 2003 invasion the Iraqi government has at least not used Nerve Gas on it's civilian population.
You might be right in that, although have a read through that article I linked - it spends a considerable amount of time debating whether Ukraine really can be considered part of the West or the East.
I still think it was unwise to ever even think about courting Ukraine with regards to the EU and especially NATO (and I still maintain that with the Baltic States also) as that was tantamount to poking Russia in the eye with a stick. No matter what the Ukrainians might feel Russia considers Ukraine to be in its back garden and was never likely to take a move to the West without some sort of response.
And seeing as the Russian local foreign relations tool kit normally relies on coercion followed by violence the present situation should not be particularly surprising.