The Russian annexation of Crimea and the subsequent pressure put on Ukraine is a sign that in the future they will once more attempt to expand their nations power both militarily and politically. The lack of international action by the UN and the EU suggests that few are willing to put serious pressure on Russia to back down. This seems to follow the plan of appeasement taken with Hitler on the eve of WW2.
The people of the Ukraine seem to be sick of their government and more supportive of their Russian governments. The people of Ukraine started this revolution of sorts trying to push for Russia to take over. Unlike world war 2 where Hitler took Poland which did not want to join Germany.
Admittedly yes, the circumstances for Russian action are much different then those going into WW2. Never the less, some portions of the Ukraine population may be content with allowing Russian control but there is also a strong opposition movement in Ukraine for national unity. The people of Crimea were a largely ethnic Russian population which allows for the argument of consent of the governed/choosing which government they wish to align with. I do not rebuke the fact that it is their right to join with Russia but Russia by nature is a nation where expansion creates power. A simple step taken to protect one group can quickly become the trampling of the rights of another