A federalism amendment should correct the incursions on state authority of both the federal legislature and the federal judiciary. With that in mind, I think that it ought ideally to have the following components:
1) Make clear that the Interstate Commerce Clause of Article I, Section 8 empowers Congress only to regulate COMMERCE that is INTERSTATE (as the Supreme Court recognized before 1937);
2) Empower individual taxpayers and state governments to bring suit for injunctive relief in case Congress exceeds the bounds of its powers, as clarified by this amendment (lawyers call this giving individuals and states standing to sue for injunctive relief) and declare that these questions are justiciable (not “political questions” that the federal courts should dodge);
3) Make clear that the Due Process Clause of the Fourteenth Amendment is about nothing other than Due Process in judicial proceedings — that is, that it doesn’t give federal courts power to invent rights unknown to the ratifiers and does not make the federal Bill of Rights enforceable by federal judges against the states;
4) Repeal the 17th Amendment *and* give the state legislatures the power of recall over US senators (and thus give state legislatures a check on Congress’s tendency to usurp state legislative authority);
5) Require a balanced federal budget except in time of war declared by Congress;
6) Empower state legislatures to overturn federal judges’ constitutional decisions. This could be done by saying that if 2/3 of legislatures vote to do so, it is done, or in some other way.
Of course, which of these would be advocated is a political decision. The ones that are absolutely essential are #1 (which would go far to rein in Congress’s claim of power to legislate in regard to any question that comes to mind), #2 (which would make #1 judicially enforceable, and without which #1 would have no force), and #3 (which would eliminate the federal courts’
chief justification for the wide-ranging legislative authority they now exercise).