As a system of government, federalism has a number of distinct advantages. For one thing, it disperses political power instead of concentrating it at the center. Such a dispersal of power makes it more difficult for a democracy to degenerate into tyranny.
When the Founding Fathers established the American system of federalism, it was this consideration more than any other that was uppermost in their minds. The Americans had only recently overthrown what they saw as the tyrannical rule of the British by defeating them in the Revolutionary War. The last thing they wanted was to see a similar form of tyranny reestablished on American soil. Hence the system of federalism that, it was hoped, would prevent the central governing power from getting too powerful.
One further advantage of federalism is that is is generally more responsive to local needs. In most areas of policy, a “one size fits all” approach is completely inappropriate. Different communities have different needs, and those needs are arguably better served by a federalist system in which strong organs of state and local government can more quickly respond to them. Decisions taken at a local level tend to be based on a much better awareness of the specific local conditions than those taken by central government. In turn, this generally leads to a greater degree of confidence in the workings of state and local government, whose institutions tend to be more highly regarded than federal institutions.