Federalism, a defining force in American politics, is a system of government where two or more governments share authority over the same territory. This is just the case in the United States where our national government shares power with each state to govern its citizens. Today there exists a cooperative federalist system in which its primary features include the sharing of functions between state and national governments along with exclusive powers for each as well. By sharing powers there exists a boundary to the excessiveness in which both states and the national government can exercise their power.
             With the shear size and diversity that is the United States it is easy to see that one single authority would not be feasible. For all voices to be heard, there needs to be an authority for the concerns of citizens that share a common area. This is where the states come into play. The constitution places all power not reserved for the federal government to be for the states in the 10th amendment. These include such powers as controlling roads, sanitation, and education (although the federal government does have some influence in education through aid for the most part it's up to the states to decide).
             The majority of state power seems to be focused on locality, i.e. New York 's state government is focused on the concern of New Yorkers, rather than that of anybody else. They also can pass their own laws as long as it is constitutional and they even have their own constitutions, but these are very complex and constantly changing. I believe that allowing the states to deal with their own concerns allows for a more efficient government in which they can deal with their own issues, it only makes since that matters that concern all citizens and states should be reserved for the national government.
             The national government also has its reserved powers. These include common defense and the supremacy clause, in which all citi...