Sometimes SCOTUS is the last word - or their interpretation of the limits of federal government power is the last word. But, depending on the case, Congress can step up and do its job (fat chance, I know), and overrule a SCOTUS decision. I think early wiretapping laws and phone privacy are Congressional constructs, in light of SCOTUS allowing warrantless wiretapping shortly after phones had been invented, just to pick an example.
As an academic point, there is also the remedy of impeachment, for judges who credibly stray outside of constitutional boundaries. Congress will never use that.
-- I feel that we Conservatives have rolled over for the black robes of many courts and THAT is why we are in a slow boat to Socialist China in our own current government! --
Courts and Congress working in cahoots. Powerful forces at work. There's a sort of Gordian knot, and the people are none too concerned over having a federal government that is radically outside of its boundaries.
One of the ultimate forms of legal checks-and-balances has been pretty much ignored.
Article III “The trial of ALL CRIMES shall be IN THE STATE...”
This was slightly amended by the sixth amendment, The trial of all crimes shall be in the state or the district where committed... but the sixth amendment DID NOTHING TO EXPAND THE FEDERAL DISTRICT BEYOND IT’S ORIGINAL MEANING!!!
The FEDERAL DISTRICT IS THE TEN SQUARE MILES CEDED FOR THE PLACE OF GOVERNMENT, FORTS, DOCKS, PORTS OF ENTRY, AND ANY LAND LAWFULLY CEDED TO THE FEDERAL GOVERNMENT!!!
So if some alphabet agency busts down your door for not having a low flow toilet, they are supposed to get charges filed against you IN THE STATE!!! IN A STATE COURT and let things go from there!!!!
The states NEVER, either before or after the ratification, gave the federal government ANY KIND OF GENERAL POLICE POWER!! NEVER!
That’s just about the ultimate power of sovereignty, and they just did not give it up. Plain and simple.