The American Founders wanted to build a republic that would endure, but history warned them that republics are fragile and short-lived. They concluded that size was a factor. Rome, for example, lost its republican institutions as it expanded.
The Founders' solution was brilliant. A large, continental nation could not be a republic, but it could be a federation of republics. The result was phenomenally successful.
Sadly, the temptation to centralize and bureaucratize has been indulged many times. It is unlikely we can ever return the Federal Government to its original design.
Except . . . fully half the states of the U.S. are larger in population than the U.S. at its founding. Furthermore, mobility has allowed us to sort ourselves into ever more red and blue regions.
Why couldn't we divide into several separate nations? Why shouldn't we?
How would you redraw the map of the U.S., were you dictator for a day? Where are the fault lines? What is the optimal size of a republic in the modern world? Should Canada or the UK split? C'mon, people: let's redraw the map!