This document defines and explains the concept of federalism. It discusses how federalism divides power between the central/federal government and state governments. It also describes how federalism has evolved from a system of "dual federalism" where each level was supreme, to today's "cooperative federalism" where powers are shared through grants and mandates. The advantages of federalism for democracy are increasing citizen participation and allowing local problems to be solved locally, while the disadvantages can include unequal services across states and too many levels of government.