What is federalism?

Answer 1

"Federalism is the political philosophy that underlies a system of government in which sovereignty is constitutionally divided between a central governing authority and constituent political units (like states or provinces), creating what is often called a federation. Proponents are often called federalists. In Canada and Europe, "federalist" is often used to describe those who favor a stronger federal government (or European Union government) and weaker provincial governments. The same is historically true in the United States, with those who generally favor a confederation, or weaker federal government and stronger state governments, being called "anti-federalists". However, in recent years in America "federalism" has come to mean something closer to confederacy."
- http://en.wikipedia.org/wiki/Federalism

Answer 2

Federalism is a system with divided and diffused powers between the various levels of government. Which each level has there expressed limits.