There is no doubt that secession of Crimea was engineered by Russia. And zombifying TV propaganda and presense of Russian army (even if it is on restraining mission only) both played their roles. But the fact is that significant number of people in Crimea really wanted to unite with Russia. I would not be surprised if there are more pro-russian people in Crimea than pro-EU people in Ukraine. Ukraine got into a turmoil and there is a lot of uncertainty at the moment (I am not saying that russians needed immediate protection).
Many russians consider Crimea to be a russian territory populated with russians that for some strange and unfair chain of events happened to be in a foreign country. Now the president of this country is illegaly overthrown, constitution replaced, the army is demoralized and disfunctional.
Crimea as a part of Ukraine has been a sore thumb for russians since the collapse of the Soviet Union (before that the fact that Crimea was a part of Ukranian SSR was just a formality). One of important parts of russian history is about getting access to the seas, and getting naval dominance or at least recognition.Nowdays it seems to be an outdated view, but getting Crimea from Ottoman Empire and establishing russian fleet on the Black sea is considered to be a part of the russian glory (if there still is such a thing
![Smile :) :)](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
. Having the russian fleet stationed in a foreign country and permanent possibility to be thrown out was humiliating at least. So, the idea of getting Crimea back was popular for quite a long time.
For people who are asking "what is going to be next?" and counting russians here and there, try to understand it please. The idea of getting back Latvia or Azerbaijan is not popular among the russians. Putin can get better popular support and boost his ratings if he demands the USA to return Alaska back to Russia, than if he invades any former Soviet Republics. So, I think the Crimea is pretty much a one time and the only deal.
Originally the only question on the referendum was supposed to be about getting a greater autonomy within the Ukraine. Only when the West said that sanctions are inevitable, the question about direct unification with Russia was added. Basically, all this opens another can of worms (or may be it has already open since the West supported separation of Kosovo from Yugoslavia). There will be pro-russian unrecognized states that will ask to be included into Russia. And there is also a possibility of referendums in Chechnia, Tatarstan and other subjects of Russian Federation to get out of Russia. Even though conducting such a referendum would not be legal according to russian laws (ironic, huh?). And, yes, more sanctions from EU and USA. Engineering "color revolutions" and "arab springs" is their prerrogative. When somebody else does it, it suddently becomes highly illegal and "unprecedented".