Granted, that was more reasoned than the usual batshit crazy analyses that they post to support their radical left-wing agenda. However, I think that it is wrong in one fundamental respect: there is no reason for the US to waste time and resources fighting for influence in Eastern Europe with anyone. If the EU cares, okay, fine, run with it, but why should we care? Russia is acting within the old Soviet borders, which frankly shouldn't concern us much (unless it were to intervene in the Baltics, which is more problematic for lots and lots of reasons I don't need to remind you about). Let's not forget that the agreements that we made back in the early 1990s promised that NATO wouldn't expand into the former Soviet Union, that the US wouldn't position troops or assets farther East than they already were and that we wouldn't destabilize Russia. The West broke all of those promises, and it's clear that the West was supporting the Euromaidan people (though of course we said "fuck the EU", per Victoria Nuland).

The response from Russia is heavy-handed, yes, but has Russia ever responded in a subtle fashion?

What I believe would happen if the Russian intervention went beyond Crimea and led to a chilling of relations is that the US will have a choice: will the US and EU cut themselves off, through sanctions, from a growing list of countries that could theoretically form an alternative market (Russia, China, Iran, lots of third world countries that wouldn't sign on to Western sanctions like India, Indonesia, the UAE, African countries), or do we simply recognize that we have moved from the days of "the sole superpower" to a new "great powers" sort of arrangement?

If the situation goes in the direction I think it will, it will certainly shake up the existing status quo in the world. The impotence of the UN, long on display, will lead to alternative power structures taking the lead. It may be more dangerous, but it will also probably be much more honest and straightforward, rather than hiding behind the hypocrisy and absurdity of the UN.