If the GOP were smart they would use this to their advantage. There is no reason to secede if more power is pushed back to the states. Then they can govern as they please. Take this craziness and use it to advance the principles of limited government.
Off the top of my head, the Ninth Amendment comes to mind, if memory serves me...
Possibly also the enumerated rights reserved to the states, like the definition of citizenship.
Also the absolute right to decide the form and conditions of voting, including the right to require voter ID, the Constitutional citations not changed by amendment I have not memorized...