I don’t think there is going to be any significant US involvement, which may be good for everyone. American national interest is in respect for the treaties US signed, such as the Budapest Memorandum (not really a treaty anyway) and in shoring up NATO deterrent in the Balt states. It is primarily an European crisis.
Amen to that.
Besides, I see all the stuff about the evil Putin and horrible Russians but I have to put myself in the shoes of Putin and several small European countries and see the world from that perspective.
From that perspective, who actively helped overthrow the governments of Algeria and Libya? Who was and still is helping the Muslim Brotherhood in Egypt? Who is arming the horrible Muslim butchers and mad dogs in Syria?
The answer to everyone of those questions is "the US". Why would Putin not think the US is behind the sort of mass violence that was going on in the Ukraine when it's exactly like what kicked off the coups in the Middle East? Why would a weak government in Europe, looking at a sizable population of ever more militant Muzzies in their country, trust the US to not help overthrow the existing government in order to help form a Muzzie state in all or part of their country? Who do you think Spain expects to support the totally absurd, "right of return" demands Muzzies are making regarding their returning to Spain; the US or Russia?
The elected government in the Ukraine was overthrown, and yes, any change of government prior to the elections that were scheduled for later in the year is an illegal overthrow of the government. What, the mob didn't think they could get enough votes in the election or they didn't think they wanted their backers to get tired of waiting since so much EU money has already been bet on the Ukraine being part of the EU?
Whatever the case, Putin has to look at the situation realistically and he has no reason to believe that Europe or the US will do anything other than support the collapse of the Ukraine into nothing but an EU puppet with porous borders that welcomes Muzzies who want to get to Russia.
Could he have done something else when the news shows had crowds demanding that all Russians be thrown out of the Ukraine and more than a few skinhead types with Nazi flags were making plenty of noise? Personally, I don't see what diplomatic options he had and I see a lot of reasons why he wouldn't want a horde of Russian people fleeing into Russia from the Ukraine if things get worse.
Just thinking things through, then, I don't see why people think anyone in their right mind would not suspect the US and NATO are the driving force behind what's going on in the Ukraine. Any way it goes, the Europeans are going to deal with Russia and ignore the US because they, too, know they can't really trust the US to not be meddling in their internal affairs.