The Rebirth of Nullification?

Evidently, the friendly folks who have been fighting to deprive their constituents of access to legally mandated healthcare have set their sights a bit higher... They're now working for a Constitutional amendment to allow a 2/3 majority of state legislatures to override any federal law. As such, I'd imagine it doesn't raise Constitutional questions itself (you can amend any part of the Constitution except for the provision that each state gets two Senators). It's an interesting idea, since after all Constitutional amendments themselves have to be approved by 3/4 of states, and much more benign than the original concept of nullification which more or less was the view that states could pick and choose between federal laws. However, given where the proposal is coming from, I have my doubts. Now, if it were designed to repeal No Child Left Behind...