Lifted this from Wikipedia, which in turn was copied from an article Thompson wrote that was featured at Townhall.com, among other sites. I think it bears repeating.
Our government, under our Constitution, was established upon the principles of Federalism -- that the federal government would have limited enumerated powers and the rest would be left to the states. It not only prevented tyranny, it just made good sense. States become laboratories for democracy and experiment with different kinds of laws. One state might try one welfare reform approach, for example. Another state might try another approach. One would work and the other would not. The federal welfare reform law resulted from just this process. Federalism also allows for the diversity that exists among the country's people. Citizens of our various states have different views as to how traditional state responsibilities should be handled. This way, states compete with each other to attract people and businesses -- and that is a good thing.
Does that not make absolutely perfect sense???