Russian situation:
The current ruler of Russia, Vladimir Putin runs a authoritarian regime quite similar to a dictatorship which the Russian people seem never to get out from under.  He has allegedly reaped approximately 75 billion making Russia a plutocracy.   Russia also has quite a number of plutocracy individuals.  The smarter one’s have figured out how to live with Putin as a self determined dictator (that they can barely control).  His administration has led to some surprising good economic, political and social changes.  Putin may have expansion motivations and is antagonistic toward NATO for this reason.  NATO’s intention is to thwart possible Russian military expansion into Europe states some of which were former Soviet “members”.  One of Putin’s possible intention is to allegedly restore the former Soviet Empire.  Put another way, he wants to expand the current Russia by getting back portions that were allowed to break away.  The fear among the rest of Europe is his intentions may be further into Europe.

Wikipedia: Putin allegedly declared at a NATO-Russia summit in 2008 that if Ukraine joined NATO Russia could contend to annex the Ukrainian East and Crimea.

Ukraine situation:
The “former” leader of the Ukraine, Victor Yanukovych, not only was close to Putin in political thinking but allegedly raping his county of wealth.  The point here is that Yanukovych has three attractive items in his resume that attract Putin.  He is the alleged current legal (temperately deposed) leader.  He professes to support Putin’s expansion policies.  He is immensely rich.  He allegedly stole 12 billion, by plundering the wealth of his nation.  This “former” leader of the Ukraine, Viktor Yanukovych, professed he was open to the proposed creation of a Eurasian Union thus falling in line with Putin’s goals.  The Ukraine would thus come under the Russian government control and meeting one of Putin’s dreams of a solidified and expanded Soviet empire.  But, the Ukraine people are fed up with corruption, unemployment and inflation. It seems that the people of western Ukraine have seen the results of unrestricted thieving plutocracy.  They want a better life and are willing to fight.

Crimea situation:
Crimea is an immensely important strategic military site for Russia.  It houses the Russian Black Sea Fleet.  This nearly complete island just south of the Ukraine has been in turmoil in that Russia and Ukraine have had a couple of crisis situations take place over how this near island is administered.  The latest crisis, February 2014 came about with Ukraine dictating that only Ukrainian be the state language, a most stupid move.  Problem is that most of the Crimea citizens, 58% are ethnic Russians.

Summary:
The Russian military needs Crimea under their control.  Putin needs Crimea and would love to also to have Ukraine.  Ukraine wants Crimea back but they do not have any power to make this happen  except to rely upon some far away countries to apply trade and financial pressure.  Europe and the United States will dance across the floor with political postures making themselves look like they really care.  Putin respects power factors more than anything else.  Trade restrictions and condemnations by foreign governments mean nothing to him until it hurts in some way.   Putin will get whatever he wants.  He holds a powerful position.