Key Fact
One justification commonly given for federalism is that we live in a large, diverse country with lots of different geographic circumstances. It may not be the case that one size fits everybody. You want to have governments at the local levels because the conditions are different. In downtown Manhattan, downtown Los Angeles, San Francisco, or Chicago you have a higher density of people. You might want to have different rules there than in North Carolina. The best decision maker is very close to the ground because of the very different kinds of populations and geographies we have in the United States.