Are you in your first year of law school or something? Jason is correct, the United States is a collection of separate nations which ceded a level of sovereignty to a central government; that central government having been created by those separate nations. While the ratified federal constitution is the supreme law of the land, it is only supreme as to those areas specified in the constitution. It seems most federal laws are somehow tied to the commerce clause or the 14th amendment's enforcement provisions. But the federal government does not have many traditional state powers. For example, there is no federal marriage license, no divorce proceedings in federal court, no federal probate. That the states retain a level of sovereignty is evident by the requirement that they - not Congress - are they final decider on any changes to the federal constitution. And I'd be remiss not to add that the federal rules of civil procedure have nothing to do with this discussion whatsoever.