My point on the use of Federalism in SCOTUS decisions is that the Liberals on the Court, and to a lesser extent the Conservatives, tend to read Federalism differently depending on how each party views the particular right in question. For example, the Court, particularly on the Left, has no patience with Federalism when it comes to the First Amendment -- or the Fourth, for that matter. There is less severe Federal scrutiny of Second and Fifth Amendment (Takings) cases. Compare and contrast the Opinions next week on the Ten Commandments case with the Takings case this week -- why is it such a Federal issue if a STATE posts the Ten Commandments, but not if a State takes private property and gives it to another private person? For that matter, Conservatives who scream bloody murder about Federal intervention in state abortion laws were screaming for the President to use Federal Agents to storm a hospice in Florida and set Terry Schiavo free. All sides of the political spectrum appear to be Federalists when it works for them, and Centrists when it doesn't.
Personally, I wish Federalism was stronger than it is today, but that doesn't mean I believe states have the right to enslave citizens or deprive people of basic rights. The proper division of Federal / State power has been the exclusive province of the Courts for decades; I think that it is long past time for this to be an honest debate politically.