@Red Viking another very good post (I won't quote it because of its length).
I think we mostly agree, except on the issue of NATO which becomes a chicken/egg scenario depending on viewpoint, really.
This is very true. The only thing I'd say is that any country (considered a military power) would respond almost identically to the Russians if faced with an encroachment upon their traditional sphere of influence. There was an agreement with NATO made in the 80s that they would not advance toward traditionally Russian controlled spheres. NATO has sought to break that agreement at every turn since. As Stockham notes:
So, whilst I agree that Russian annexation can't be given a free hand, it does have to be seen in a wider context -- one that can't simply exculpate NATO's involvement. Sure, countries can decide to join NATO, but NATO should never have sought to expand to the East, and should have simply made known that those applications would be ignored. In all honesty, NATO hasn't had any legitimacy since the Cold War. We'll likely disagree on this, but I can at least understand your viewpoint (it's a relatively common one, after all).