Why Ukraine matters so much

CNN's Jim Sciutto is at the Magic Wall to explain why Ukraine has become such an important battleground between Russia and the West and what's really at the heart of the crisis.

NOTE: Those 22% of Americans who say the U.S. should act as the "world's policeman" were part of a CNN/ORC Poll conducted in September 2013, just as the U.S. was contemplating a strike in Syria.