We're increasingly starting to see this happen before our very eyes right now. One area is laws banning marijuana, another is in granting de-facto citizenship rights to illegal aliens. Many states are becoming bolder and bolder in open defiance of federal statute in these areas.
Wait until it's a form of state defiance on federal tax monies, particularly if it takes the form of federally mandated *standards* for the return of state federal highway funding. If the feds fail to return state tax dollars in response to a state failure to mandate federally-directed speed limits, motorcycle helmet laws, or restroom standards at highway rest areas, don't be surprised if a state quits collecting the federal tax on gasoline sold in the state and dumps 50 tons of sand here and there on their interstate highways, deferring maintenance until the feds return to their senses.
And I've had conversations with at least one congressman who's become a Second Amendment absolutist not because he sees it as so envisioned by the founders or for the benefits it brings to American citizens, both of which he acknowledges, but because he really fears the reaction of his state government in the event of federal excess in attempting to disarm the citizens.
-archy-/-
The list will be expanded, as it should be.