Why is supranationalism important?
Supranationalism is the idea that countries need to give up some of their sovereignty to larger organizations like the EU. This idea is important only because it is affecting Europe to a large degree.
The EU is, if we take it as one economy, the largest economy in the world. It seems to be moving towards more of a supranational body as it tries to tell countries like Greece what to do with their internal finances. Since the health of European economies affects the whole world, the idea of supranationalism is important to the whole world.