That's my larger point here.  Putin is determined to use military force to secure his objectives and is willing to risk confrontation with the US to do it, betting that the US won't engage because that would be game over.  An anti-Russian government in the Ukraine is a major threat to Russia and to Putin's ability to govern in Russia. (As I've noted before, Ukrainians, despite the language differences, are a lot more like Russians that Texans are like Americans. The US would never stand for Russian-supported Tea Party government declaring in Texas, or even in Canada, so we should presume that Putin is highly motivated to secure either an allied government in the Ukraine or to annex at least eastern Ukraine.  

None of this has anything to do with energy. It's all about power, specifically Putin's power within Russia.  Unless we are willing to out-Putin Putin by quickly inserting military forces in the Eastern Ukraine (which is, btw, technically quite possible. US airborne forces could have 10,000 troops in eastern Ukraine within a couple of hours given US military assets already in Europe. Russia would not be able to move in ahead of them and would risk a shooting war if they tried, which is our gamble that Putin is unwilling to do.)  it makes more sense to tone it down and be ready and willing to just give Putin what he needs in the Ukraine.  So far this seems to be what is happening.